CRINK Security Ties

• Military and security cooperation among China, Russia, Iran, and North Korea (CRINK) accelerated significantly after Russia’s full-scale invasion of Ukraine in 2022. This includes a surge in transfers of arms and dual-use goods, a new mutual defense pact, and more frequent and diversified joint military exercises.

• Observable security cooperation has taken place bilaterally or trilaterally, with no discernable official cooperation taking place quadrilaterally. However, there have been instances of Chinese, Iranian, and North Korean players working together in diffuse ways to support Russia’s war in Ukraine. Overall, the China-Russia security partnership is the most robust, but North Korea and Iran have quickly strengthened security cooperation as well, primarily with Russia.

• Despite strengthened ties among CRINK countries, the four countries are not always on the same page. To date, limited overt military support for Iran following attacks by Israel and the United States showcased how various factors—transactional calculations, power asymmetries, geographic distance, simultaneity of conflict and fatigue, U.S. military involvement, different interests, and elements of distrust—affect the willingness of CRINK countries to directly support one another via military means.

• Overall, the two larger powers—China and Russia—anchor CRINK cooperation. They have much more to offer to incentivize others to support them, and they are the most closely aligned bilateral actors. China, Russia, and North Korea are the trio most likely to support one another in times of need.

Introduction

The United States and many of its allies and partners have become increasingly concerned about growing alignment and cooperation among CRINK countries, prompting some to dub them the “axis of upheaval” or “axis of authoritarianism.” This brief explores available evidence to assess the extent of military and security cooperation among the CRINK countries. It first analyzes significant changes since Russia’s 2022 full-scale invasion of Ukraine and then explores CRINK responses to attacks on Iran that began in 2024 and escalated in 2025.

Key data points considered in this analysis include transfers of weapons and dual-use goods, joint military exercises, and defense pacts.1 This analysis is limited to assessing activities discernible from open-source information. Nevertheless, the available evidence points to intensifying security cooperation among the CRINK countries, with notable limitations.

The Ukraine War Has Accelerated CRINK Security Cooperation

Russia’s 2022 invasion of Ukraine has brought into sharp focus the growing alignment among CRINK countries. Russia’s ability to prosecute the war in Ukraine has been sustained in large part by various forms of support from China, Iran, and North Korea. Russia has reciprocated in kind, highlighting a transactional aspect of the relationships. There has also been growing cooperation among the four countries through joint military exercises.

Arms Transfers

Weapons transfers have long been an area of cooperation among CRINK countries, and they are often tied to regional tensions and conflicts. Amid the Iran-Iraq War of the 1980s, North Korea sold Iran Scud-B/Hwasong-5 short-range ballistic missiles (SRBMs), and it later provided newer Scud-C/Hwasong 6s in the 1990s. China also sold Iran some $4.8 billion worth of aircraft, missiles, artillery, and tanks through Bolivia, Brazil, and Pakistan as intermediaries in the 1980s, and the Soviet Union (and then Russia) intermittently supplied Iran with various conventional arms, including aircraft, submarines, tanks, and air defense systems. With the easing of UN sanctions on Iran in 2015, Moscow began deliveries of Russian S-300 air defense systems that had been previously withheld.

North Korea benefited from Chinese and Russian arms sales as well. In the 1980s and 1990s, China intermittently supplied North Korea with hardware including 40 F-7 (MiG-21) fighter jets, as well as submarines, transport aircraft, and Silkworm anti-ship missiles. Russia provided Pyongyang with MiG-29 fighters, air defense systems, and more.

China has not overtly imported major systems from Iran or North Korea over the years, but it relied heavily on Russian equipment to rapidly modernize its military. Between 1990 and 2005, China placed several orders that included 270 Su-27 and Su-30 fighters at a total cost of approximately $10–$11 billion. It also ordered eight Russian Kilo-class submarines, four Sovremenny-class destroyers, thousands of missiles, several S-300 surface-to-air missile (SAM) systems, and more.

Prior to 2022, the flow of arms was primarily from Russia to the other three countries. Russia has long been a giant in the global arms trade, and the only country in recent decades to rival U.S. arms exports. According to arms trade data from the Stockholm International Peace Research Institute (SIPRI), between 1980 and 2021, Russia provided about 78 percent of China’s arms imports, 73 percent of North Korea’s, and 40 percent of Iran’s. However, both Iran and North Korea weaned themselves off Russian and other arms imports by the 2010s, and China’s imports of Russian equipment fell to a fraction of their previous highs from the early 2000s.

This pattern of arms transfers from Russia to other CRINK countries reversed after 2022 as Russia increasingly relied on arms from Iran and North Korea to sustain its military operations in Ukraine. Iran reportedly transferred around 400 Fateh-110 family SRBMs, anti-tank missiles, artillery shells, and ammunition to Russia. Perhaps most significantly, Iran supplied thousands of Shahed-131 and Shahed-136 loitering munitions (suicide drones) and armed Mohajer-6 drones and accompanying munitions.

As the Ukraine war continued and Russia’s defense industry recovered, Iran supplemented weapons sales with technology sharing and personnel support. Under a deal dating back to late 2022, Russia set up a factory to manufacture licensed versions of Iranian designs, producing up to 6,000 drones annually. Iran has also shared advanced modifications—including AI guidance, anti-jamming systems, and enhanced warheads—with Russia, improving strike accuracy and battlefield lethality. Tehran has also sent Islamic Revolutionary Guards Corps drone trainers and technicians to Crimea and potentially other Russian-occupied regions.

North Korea has also contributed substantially to Russia’s war efforts. In October 2022, it was reported that Russia’s Wagner Group purchased North Korean weapons to fight in Ukraine. Pyongyang significantly stepped up support for Russia around September 2023, and since then, reports suggest North Korea has transferred massive amounts of ammunition and equipment to Russia, including millions of artillery shells, self-propelled guns, and multiple-launch rocket systems (MLRS), ballistic missiles, and SAM systems, among other assets.

▲ Figure 1: Chinese, Russian, Iranian, and North Korean Arms Imports by Source. Source: SIPRI Arms Transfers Database, Stockholm International Peace Research Institute, updated March 2025.

Dual-Use Goods and Other Support

Unlike Iran and North Korea, China has not overtly supplied Russia with lethal aid, but Beijing’s contributions to the war effort have nevertheless been immense. Despite claiming to be neutral, China has provided Russia with critical commercial and dual-use goods that directly help to support Russian military operations in Ukraine.

Over the course of the war, China has ramped up exports to Russia of “high-priority items,” a set of 50 dual-use goods including computer chips, telecommunications gear, machine tools, radars, and sensors that are essential to producing military systems. Russia lacks the capacity to produce many of these goods in sufficient quantities, but China’s massive manufacturing sector can produce many of them at immense scale.

Chinese sales have enabled Russia’s industrial production of military goods in the face of Western sanctions. Chinese advanced machinery was reported to have tripled Russian Iskander-M ballistic missile production from 2023 to 2024, and in 2024 China accounted for 70 percent of Russia’s imports of ammonium perchlorate, an essential ingredient in ballistic missile fuel.

China is also the unrivaled global leader in commercial drones, which have played a crucial part in the Ukraine conflict. In recent years, China provided Russia with drone bodies, lithium batteries, and fiber-optic cables—the critical components for fiber-optic drones. These drones, which are wired through fiber-optic cables rather than wirelessly controlled, have become central to the war in Ukraine thanks to their ability to operate in environments where electronic jamming limits the effectiveness of wireless drones.

Collectively, these developments have generated new areas of diffuse trilateral and even quadrilateral cooperation among CRINK countries. For example, North Korean workers have been sent to Russia to work in drone factories that rely on Iranian technologies and funding to produce drones made from Chinese equipment. The United States and Europe have also expressed concerns that North Korea could transship some weapons to Russia through Iran in ways reminiscent to how China passed weapons to Iran through intermediaries in the 1980s.

A New Defense Pact and North Korea’s Deployments to Ukraine

On top of providing weapons and equipment, one of the most significant developments following Russia’s invasion of Ukraine is the establishment of a new Russia-North Korea defense pact. In June 2024, Russian President Vladimir Putin visited Pyongyang and signed a “comprehensive strategic partnership” treaty that committed them to mutually supporting each other if one is attacked. Prior to this, China and North Korea were the only two CRINK countries to have a formal treaty with mutual defense obligations.

Shortly after the treaty was signed, North Korea deployed an estimated 14,000–15,000 troops and thousands of additional workers to Russia over late 2024 and early 2025. The direct contribution of troops into the conflict marked a watershed moment and put North Korea in a distinctive position compared to Iran, which has provided arms but not overt troop deployments, and China, which has provided an immense amount of dual-use goods but has not directly provided lethal aid or deployed troops.

▲ Table 1: Chinese, Iranian, and North Korean Security Cooperation with Russia during the Ukraine War. Source: Authors’ analysis of media reports and official statements.

CRINK Transactionalism and Russian Reciprocation

China, Iran, and North Korea’s assistance to Russia not only strengthened their relationships with Moscow, but also allowed them to capitalize on Russia’s needs to extract military and security benefits for themselves. Transactional and self-interested motives are key factors driving CRINK cooperation.

China’s support for Russia’s war in Ukraine likely opened the door for key Russian military assistance. Since 2023, there have been reports of Russia assisting the development of China’s new-generation Type 096 nuclear ballistic missile submarine by providing quieting and propulsion technologies. If accurate, this marks a major shift in Russia’s willingness to offer China advanced military technologies, an area where it has historically had a lead over China. In another show of cooperation, Chinese military officers were able to tour Russian front lines to learn tactical lessons.

Even more significant, leaked documents revealed that in October 2024, Russia agreed to sell China a substantial amount of equipment relevant to an invasion of Taiwan, including 37 BMD-4M light amphibious vehicles, 11 Sprut-SDM1 self-propelled anti-tank guns, 11 BTR-MDM airborne armored personnel carriers, plus command and observation vehicles and parachute systems for airdropping heavy loads. The leaked documents also showed Russia would provide training programs for Chinese paratroopers on how to use Russian equipment.

North Korea has also gained from Russia. Since 2022, Moscow reportedly supplied the country with Iranian attack drone technology, space technology assistance, air defense equipment, anti-aircraft missiles, and advanced electronic warfare systems, as well as feedback and guidance to improve its ballistic missiles. There is also speculation that Russia helped with the design and building of North Korea’s new Choe-Hyon class destroyer that was launched in 2025, and reporting that North Korea received a nuclear submarine reactor in exchange for its troop contributions. The CSIS Korea Chair estimates that North Korea earned between $9.6 and $12.3 billion from its provision of equipment to Russia—a massive boon for North Korea’s underdeveloped economy, whose total trade amounted to just $2.7 billion in 2024.

For its part, Iran has sought to tap into Russia’s defense industry to recapitalize its own diminished military forces. Since 2023, Tehran signed deals with Russia to acquire billions of dollars’ worth of military equipment from Moscow, including advanced Su-35 fighter jets, attack helicopters, radars, Yak-130 trainer aircraft, and S-400 air defense systems.

Joint Military Exercises

The strengthening of security ties among the four countries since the Ukraine war is also manifested through more joint military exercises.

According to the authors’ dataset of joint military exercises, there were 61 exercises involving at least two CRINK countries between 2003 (when the first China-Russia exercise occurred) and 2021 (the year before Russia’s invasion of Ukraine). That averages to 3.2 exercises per year.2 From the start of 2022 through August 2025, there were 35 exercises involving CRINK countries—an annualized average of 9.5 exercises per year.

▲ Figure 2: Joint Military Exercises Among China, Russia, Iran, and North Korea. Source: CSIS China Power Project.

China and Russia are by far the leading actors on this front. China-Russia bilateral exercises account for 83 percent of all CRINK-related exercises, and either China or Russia participated in all recorded CRINK exercises.

Yet CRINK trilateral cooperation through joint exercises has become more commonplace in recent years. In 2019, China, Russia, and Iran conducted the first of their trilateral exercises, which have become annual occurrences since 2022. In another first, Iran joined multilateral drills (which included China and Russia) organized through the Shanghai Cooperation Organization (SCO) in 2024.

▲ Table 2: Multilateral Military Exercises Involving China, Russia, Iran, and North Korea. Source: CSIS China Power Project.

Even North Korea has begun to dip its toes into joint exercises. Pyongyang historically shunned participation in international military exercises, but that changed when North Korea joined Russia’s “Ocean-2024” naval drills as an observer. China also participated in part of those drills, making it a rare instance of China-Russia-North Korea trilateral activity.

There are limits to the significance of these exercises. CRINK militaries have not reached the level of interoperability demonstrated by the United States and its NATO allies, which have experience conducting joint combat operations and exercises over multiple decades. Nevertheless, joint exercises are an increasingly visible sign of the growing cooperation among CRINK countries.

Iran’s Conflicts and the Limits of CRINK Cooperation

Just as Russia’s February 2022 invasion of Ukraine marked a watershed moment for CRINK countries, so too have Iran’s conflicts in the Middle East since April 2024. However, whereas the Ukraine war catalyzed CRINK security cooperation across several dimensions, Iran’s conflicts have so far shown mixed levels of security cooperation and highlighted limits to the countries’ relations.

Following the start of direct hostilities in April 2024—but before strikes on Iran’s nuclear facilities—there was noteworthy support for Iran and its proxies. In February 2025, Chinese manufacturers delivered approximately 1,000 tons of sodium perchlorate, a critical precursor for solid rocket propellant, to Iran.3 Then, in early June 2025, reports emerged that Iran placed orders from China for thousands of tons of additional missile fuels.

Separately, in April 2025, the U.S. State Department accused a Chinese firm, Chang Guang Satellite Technology, of supporting attacks on U.S. interests by Iran-backed Houthi fighters. Reports indicated the company was supplying Houthi rebels with imagery to target U.S. warships and international vessels in the Red Sea.

Once Iran’s conflicts escalated and both Israel and the United States struck Iran’s nuclear facilities, however, there was lackluster military support for Iran from the other CRINK countries. In the immediate aftermath of the June 2025 strikes, China, Russia, and North Korea provided Iran with modest rhetorical support but stopped short of major displays of solidarity. In a call with Iranian Foreign Minister Seyed Abbas Araghchi, Chinese Foreign Minister Wang Yi condemned Israeli attacks on Iran. Russia and North Korea followed suit with similar condemnations, and Russia joined China in pressing for a ceasefire agreement in the UN Security Council.

A few weeks after Israeli and U.S. strikes on Iran, conflicting reports emerged claiming that China was providing SAM systems such as the HQ-9B to Iran to help rebuild its defensive capabilities. However, these reports were unsubstantiated, and Chinese authorities, including the Chinese embassy in Israel, put out official statements denying them.

In the months that followed, China and Russia intensified their support for Iran in a few ways. In July, China, Russia, and Iran held trilateral talks ahead of expected U.S.-Iran nuclear talks, and Russia offered to assist Iran’s efforts to grow its nuclear energy program by providing Iran with low-enriched uranium and hosting Iranian nuclear scientists at dual-use research facilities. That same month, Iranian officials signaled that Tehran is considering partnering with Beijing to use its BeiDou global positioning system as an alternative to the U.S. GPS system, which experienced disruptions in Iran during the June 2025 strikes.

Similar to its economic support for Russia to fuel its war machine, China has reaffirmed its economic support for Iran after the June 2025 strikes. That month, Beijing and Tehran reaffirmed their “strong commitment” to the 25-year Strategic Cooperation Agreement that the two countries signed in 2021. In September 2025, Xi Jinping met Iranian President Masoud Pezeshkian bilaterally on the margins of the Shanghai Cooperation Organization summit and the two leaders agreed to accelerate key infrastructure projects in the 25-year plan.

▲ Figure 3: Timeline of CRINK Support for Iran During Iran’s 2024–2025 Conflicts. Source: Authors’ analysis of media reports and official statements.

In one of the most striking instances of CRINK coordination, leaders from all four countries gathered at China’s Victory Day military parade on September 3. This was the first known instance in which leaders of all four countries were present in the same location. This was largely symbolic in terms of multilateral cooperation since there were no reported trilateral or quadrilateral meetings between the leaders. Nevertheless, it was a notable milestone for the four countries, and it offered opportunities for bilateral cooperation, with Xi Jinping meeting bilaterally with the other three countries’ leaders.

Notably, these proceedings highlighted an asymmetry among the four countries. At the parade, Xi Jinping was flanked by Vladmir Putin and Kim Jong-un while Iranian President Masoud Pezeshkian and other leaders stood behind them. This was likely because Russia and Korea were major players in the fight against Japan in World War II, which the parade was commemorating, but it was still an unmistakable display of power dynamics. As the most powerful countries, China and Russia view each other as most important. North Korea, given its shared borders with China and Russia and its possession of nuclear weapons, appears more important than Iran for both powers.

In short, there has been support for Iran and coordination among CRINK countries since the outset of Iran’s conflict, but that assistance has so far not matched what was provided to Russia. This could be a matter of timing: Significant material support for Moscow did not emerge immediately after February 2022. It took months for China, Iran, and North Korea to fully ratchet up support for Russia. China, Russia, and North Korea could still step up security aid for Iran in the future. Yet, as is discussed below, there is reason to believe there will be limits on their willingness and capacity to aid Tehran.

Conclusion

These two conflicts have demonstrated both the strengths and the limits of CRINK security ties. The war in Ukraine has shown how four countries can each bring to bear their distinctive strengths to support a common cause. North Korea has brought to the table manpower and huge quantities of less-advanced weaponry. Iran has offered large numbers of armed drones and missiles. China has harnessed its enormous economic and industrial might to backfill Russia’s wartime economy and defense industrial base while not committing troops or lethal aid. In doing so, they have all demonstrated their capacity to collectively marshal resources and capabilities in ways that are hugely challenging for the United States and its allies and partners.

At the same time, both conflicts have exposed considerable limits, which are also worth highlighting.

Transactionalism and Asymmetry of Power: Among other factors, CRINK cooperation is driven by transactional and opportunistic calculations. The two larger powers and anchors—China and Russia—have much more to offer to incentivize others to support them. Russia’s significant national power has enabled it to reciprocate to the others in ways that make it compelling for them to support Moscow’s war efforts. Conversely, Iran’s limited national power—which was been further diminished by Israeli and U.S. attacks—left it with less to offer the others. This dynamic is reinforced by the fact that Beijing and Moscow have competing interests in the Middle East, requiring them to balance their support for Iran with their relationships with other key players, including Israel and wealthy Gulf states.

Geographic Proximity: Iran is more geographically distant from the other three CRINK countries, while the other three neighbor each other. Major instability or conflict in China, Russia, or North Korea is likely to have significant spillover effects for the other two countries. In contrast, upheaval in Iran has less immediate consequences for Beijing, Moscow, or Pyongyang, affording them more flexibility to maneuver.

Simultaneity of Conflict and Fatigue: Tepid support for Iran likely also stems from the fact that it is difficult to support two simultaneous conflicts. The demands of the war in Ukraine weigh on the CRINK countries’ capacity to simultaneously commit resources to Iran. Without the Ukraine war, it is possible that all three countries could provide more support to Iran.

U.S. Military Involvement: A likely key reason for restraint in supporting Iran is U.S. involvement in the conflict. Whereas the United States has not deployed forces onto the battlefield in Ukraine, the Trump administration directly attacked Iran. Thus, intervening on Tehran’s behalf risks a direct confrontation with Washington, a confrontation that neither China, Russia, nor North Korea desires.

Differing Interests and Other Forms of Support: While all four countries share a desire to diminish the influence of the United States and its Western allies and partners, they are not fully aligned in their interests and approach. The Chinese economy is more deeply enmeshed in the global economy, which is partly why Beijing has been unwilling to risk U.S. and Western sanctions by overtly supplying Moscow with lethal aid or troops. Similarly, Beijing may be relying more on political and economic tools to support Iran than on overt military assistance.

Distrust: Despite their growing alignment, there is considerable distrust among the four countries. This was on display after Israeli and U.S. attacks on Iran when former Iranian Parliament Deputy Speaker Ali Motahari publicly stated, “Russia has given the S-400 air defense system to Turkey and Saudi Arabia, but does not give it to Iran, which has provided it with drone assistance in the war with Ukraine.” Similarly, some in Russia and China have long distrusted each other. Recent leaked Russian government documents show that actors within Moscow still deeply distrust China, and that Russia and Iran are conducting intelligence operations on each other.

Taken together, these dynamics suggest that CRINK countries are not unified actors, and there will continue to be limits on their security alignment. Yet, as recent years have shown, Washington and its allies should not discount the capacity of these four countries to work together in opposition to U.S. and allied interests. Particular attention should be paid to China and Russia as the most powerful and closely aligned bilateral actors, and China, Russia, and North Korea as the trio most likely to support each other in times of need.

Bonny Lin is director of the China Power Project and senior adviser at the Center for Strategic and International Studies (CSIS) in Washington, D.C.

Brian Hart is deputy director and fellow of the China Power Project at CSIS.

Leon Li is a research associate of the China Power Project.

Hugh Grant-Chapman is associate fellow of the China Power Project.

Truly Tinsley is associate director of the China Power Project.

Feifei Hung is a research intern of the China Power Project.