The Korean peninsula at a crossroads. How North Korea's alliance with Russia affects relations between Seoul and Pyongyang

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Today, the escalation of global conflicts has further complicated the situation. Russia's full-scale war against Ukraine has united Moscow and Pyongyang around common interests, creating new challenges for regional stability. From a strategic perspective, the peninsula finds itself at a crossroads: on the one hand, it is a platform for long-standing negotiations and potential change; on the other, it is an arena for fierce confrontation.

Against this backdrop, chronic tensions remain between the two Koreas. Previous agreements on disarmament and a ‘'common peace zone’’ have effectively lost their force. As soon as Seoul unilaterally lifted the ban on flights in the demilitarised zone in 2023, Pyongyang immediately withdrew from the same agreement and officially refused to pursue the goal of peaceful reunification. Meanwhile, North Korea is building up its military capabilities, announcing accelerated production of nuclear warheads and plans to launch several reconnaissance satellites. Accordingly, the perspective of dialogue and détente between Seoul and Pyongyang now looks more illusory than ever in recent years.

The alliance between North Korea and Russia. A new axis after 2022

The current rapprochement between North Korea and Russia has developed against the backdrop of the war in Ukraine and Moscow's isolation after 2022. Under pressure from Western sanctions, the Kremlin turned to Pyongyang for help, and Kim Jong-Un's regime, in turn, received a chance to weaken its isolation and gain new resources for survival.

Since 2022, Moscow and Pyongyang have effectively formed a long-term strategic alliance. North Korea began supplying weapons en masse to the Russian army on the front lines in Ukraine – according to the investigation, hundreds of train cars delivered millions of North Korean artillery shells to the front. Pyongyang also sent a significant military contingent to Russia – about 14,000 North Korean soldiers who took part in hostilities on the side of the Russian Federation. These arms supplies and manpower have become critical to sustaining the Russian war.

In return, the Kremlin provides the DPRK with modern technology and resources. The confirmed aspects include the transfer of new anti-aircraft missiles and air defence equipment to Pyongyang, assistance in restoring the North Korean space programme following a failed satellite launch, and the supply of petroleum products and food, despite sanctions. The scale of this support is unprecedented – North Korea now covers almost 30-50% of the Russian army's ammunition needs, while Russia is potentially ready to share military technologies with it , which were previously unavailable to Pyongyang.

The culmination of the rapprochement was the official legitimisation of the alliance. During the 2023-2024 negotiations, Moscow and Pyongyang signed a series of agreements, including a comprehensive ‘Strategic Partnership Treaty’ in June 2024 with mutual military assistance obligations. In fact, this treaty contains provisions on collective defence, thereby cementing the allied status of the two states. This step formalised the cooperation that had been rapidly deepening since the start of the full-scale Russian-Ukrainian war.

The Kim-Putin axis is emerging as a long-term factor in regional politics with a clearly anti-Western orientation. Both capitals openly appeal to the rhetoric of a ‘multipolar world’ and ‘countering Western hegemony.’ Pyongyang, for its part, is one of the few countries that provides full diplomatic support to Russia and regularly repeats the thesis of ‘brotherhood in arms’ with Moscow. Russia, in fact, supports North Korea's position on the South: it recognises the existence of two separate Korean states and legitimises their ‘hostile coexistence’. This means that the Kremlin is no longer interested in even nominally promoting inter-Korean reconciliation, like it did in the 2000s, but instead is making a bet on Kim's regime as its ally.

Thus, DPRK-Russia relations have gone far beyond the former tactical interaction. Whereas previously their cooperation was limited and transactional in nature (exchanging weapons for food or raw materials), now a full-fledged military-political alliance is taking shape. This significantly strengthens Pyongyang's position as a regional player – the North Korean army gains access to modern weapons systems and combat experience, and its nuclear and missile programmes can develop more quickly with Russian assistance. All this seriously changes the balance of power around the Korean peninsula and creates a new reality to which other neighbours (primarily South Korea) must urgently adapt.

Challenges for South Korea and response from Seoul

For the Republic of Korea, the alliance between Moscow and Pyongyang means a sharp deterioration in the security environment. On the one hand, North Korea, relying on Russian resources and technology, is becoming a much more capable and aggressive military opponent. With Russia's guaranteed support as a nuclear state and the actual supply of everything necessary to wage war, Kim Jong-un's regime feels more confident.

On the other hand, Seoul's position is under unprecedented pressure since the Cold War. The Kremlin is no longer balancing between Seoul and Pyongyang, but is openly siding with the latter. Any diplomatic initiatives by the South are met with obstacles: Pyongyang, with Moscow's support, can now reject any peace proposals from Seoul without consequences.

In 2022-2024, the South Korean government, led by conservative President Yoon Suk-Yeol, responded harshly to such challenges. Yoon called Moscow and Pyongyang's military cooperation a ‘gross violation of UN Security Council resolutions’ and threatened that Seoul would respond to it ‘extremely decisively and destructively’. During his tenure, South Korea significantly strengthened its defences: new missile defence systems and long-range missiles were purchased, cruise missiles for submarines were adopted for the navy, and the military budget increased by tens of billions of dollars.

In 2023, Seoul began indirect military support for Ukraine for the first time, providing artillery shells through intermediaries and considering direct deliveries to weaken Russia as an ally of North Korea. At the same time, South Korea intensified its sanctions policy against both regimes: it joined most Western sanctions against Russia and introduced its own restrictions on North Korean organisations and individuals involved in arms supplies.

In the diplomatic sphere, Seoul began to delegitimise the Kim-Putin relationship: at international forums, South Korean representatives called for the condemnation and cessation of arms transfers from North Korea to Russia, demanded the withdrawal of North Korean troops from Russian territory, and warned of the threat of a new nuclear alliance to the world.

A key element of Seoul's response was the rapid strengthening of cooperation with its traditional allies, the US and Japan. In 2023-2024, there was a de facto revival of the trilateral security alliance. The US deployed additional strategic assets in the region to support South Korea. In July 2023, for the first time in more than 40 years, the American nuclear-powered missile cruiser USS Kentucky entered the South Korean port of Busan with ballistic missiles on board.

Seoul, Washington and Tokyo launched regular joint military exercises, practising various operations against North Korean nuclear and missile threats. In particular, in September 2025, large-scale Freedom Edge manoeuvres were held with the participation of forces from the three countries. Over five days, the allies practised integrated missile defence, anti-ship operations and air strikes, demonstrating unity and readiness to respond jointly to any aggression from the North.

Importantly, the policy of tough deterrence against the North enjoyed broad support among South Korean society. Polls showed record consensus on the alliance with the United States: 96% of South Koreans believe that the alliance with Washington will remain necessary in the future. Against the backdrop of Kim's nuclear blackmail, support for South Korea's own nuclear option also rose sharply.

In June 2025, Lee Jae-Myung, leader of the liberal opposition, became the new president of South Korea. The change in power significantly adjusted Seoul's approach to the North Korean issue. In his inaugural speech, President Lee stated: ‘It is better to win without fighting than to win in a fight, and peace without the need to fight is the best security.’ He promised to continue to restrain the DPRK's nuclear and military provocations, but at the same time to open channels of communication with the North.

The new administration took a number of steps towards Pyongyang. In his first weeks in office, Lee Jae-Myung suspended propaganda broadcasts via loudspeakers along the inter-Korean border and banned the launch of balloons carrying leaflets from the South to the North – the very actions that had previously greatly irritated Kim Jong-Un. In August 2025, on the orders of the president, stationary loudspeakers along the demilitarised zone began to be dismantled, and civilians in South Korea were allowed to communicate freely with residents of the DPRK (provided they notified the authorities in advance) – for the first time in many years, space for private exchanges between the two countries was restored.

At the same time, Seoul came up with new peace initiatives: Lee Jae-Myung proposed that Pyongyang resume reunions of separated Korean families, increase humanitarian aid programmes for the DPRK, and resume direct talks without preconditions. In September 2025, speaking at the UN General Assembly, President Lee said he wanted a ‘new era of peaceful coexistence and renewed development’ between South and North, promising to rebuild broken trust and ‘end the vicious cycle of unnecessary tension’ on the peninsula.

Seoul's new course effectively combines two lines: on the one hand, maximum restraint and readiness for defence, and on the other - an outstretched hand for dialogue and attempts to involve the DPRK in the peace process.

Pyongyang's response to these peace signals, however, has so far been negative. The North Korean leadership has demonstratively rejected all of Lee Jae-Myung's proposals. On 28 July 2025, the sister of North Korean leader Kim Yo Jong stated that the DPRK was not interested in any policies or proposals for reconciliation from South Korea. Pyongyang believes that Lee Jae- Myung is no different from his ‘hostile’ predecessor, Yoon Suk-Yeol.

Seoul's allies. Trilateral coordination and the Trump factor

South Korea's response to the alliance between Russia and North Korea would be incomplete without close cooperation with other countries that share its concerns. First and foremost, this refers to the United States and Japan, Seoul's two key allies in the region. The last two years have seen unprecedented consolidation of this triad.

In 2024, South Korea, the US and Japan signed the Trilateral Security Cooperation Framework Agreement, agreeing on annual joint military exercises, regular high-level consultations and real-time intelligence sharing.

At the NATO summit in Washington in July 2024, the ‘illegal military cooperation’ between Russia and North Korea was directly condemned for the first time in a joint statement by NATO allies and partners from the Asia-Pacific region (the Republic of Korea, Japan, and Australia). This demonstrated that security on the Korean peninsula is now being viewed in a global context. Both Europe and Asia are uniting in the face of a common challenge from authoritarian regimes.

Seoul, for its part, has strengthened its role as a part of the Western coalition: former President Yoon Suk-Yeol attended three NATO summits, and in 2024, South Korea signed an Individually Tailored Partnership Programme (ITPP) with the Alliance, increased its contributions to defence trust funds, and began discussing with the US and the EU ways to stop  illegal arms trade with North Korea. In other words, the Republic of Korea is becoming increasingly integrated into the collective security system of democratic countries.

In early 2025, a new factor was added to this close trilateral tandem: a change of power in Washington. President Donald Trump's return to power has significantly affected regional dynamics. On the one hand, Trump continues to demonstrate military support for his allies: as mentioned, joint exercises and the deployment of US strategic weapons in Korea continue. On the other hand, his ‘America First’ foreign policy has affected the trade and economic aspects of relations with Seoul.

For example, in 2025, tensions arose due to internal US measures. A large-scale raid by immigration services at the Hyundai-LG plant in Georgia led to the arrest of hundreds of South Korean workers and caused a diplomatic scandal. Washington also threatened to impose higher tariffs on Korean exports (particularly cars and batteries), which required complex negotiations to prevent them. Seoul is concerned that the Trump administration may call into question its alliance commitments.

At the same time, Lee Jae-Myung is trying to use Trump to resume dialogue with Kim Jong-Un. As we know, Donald Trump has had direct contact with Kim Jong-un – they met in person three times in 2018-2019. After a several-year break during Biden's presidency, Trump has again expressed his willingness to resume dialogue with the North Korean leader. Lee Jae- Myung appealed to Donald Trump to become a ‘peacemaker’ and help bring Kim Jong-un back to the negotiating table. It is expected that Trump and Kim may meet at the border during the November summit of the Asia-Pacific Economic Cooperation (APEC) in South Korea. Earlier, Lee Jae-myung also asked Chinese leader Xi Jinping to facilitate the peace process and denuclearisation.

Seoul's new Russia policy

An important detail of Seoul's new course was the appearance of National Security Advisor Wi Sang-Rak in the presidential administration. Wi is a former ambassador of the Republic of Korea to Russia (2011-2015), an expert on North America, the North Korean nuclear question, and Russian relations.

Wi Sang-Rak wants to support the strengthening of cooperation with the US and Japan, but at the same time focuses on “managing relations with China, Russia, and North Korea.” In particular, he has repeatedly stated that the supply of lethal weapons to Ukraine should be “carefully considered” because “a complete end to relations with Russia” would harm Korea’s national interests.

Back in 2014, when almost the entire world insisted on new sanctions after the MH17 accident, Wi Sang-Rak openly stated that South Korea “does not plan to follow the example of the US and Europe”. He explained that Seoul was interested in close bilateral relations with Moscow, particularly for the development of trade and investment. During those years, bilateral trade reached $17.5 billion, and Korean businessmen were exploring opportunities to increase investment in the Russian economy. In his recent speeches, Wi repeatedly emphasized that dialogue with Russia should be based on a “comfortable position” for Seoul. He stated that the current defense agreement between Russia and North Korea would have “negative consequences” for inter-Korean security and relations between Moscow and Seoul.

The new government of Lee Jae-Myung seeks to prevent the deterioration of relations with China and Russia under the pretext of an alliance with the United States. In this context, Wi Sang-Rak is one of the main implementers of this policy. Under his influence, Seoul is unlikely to close “gray” or diplomatic channels with the Kremlin. Rather, South Korea may try to establish certain “rules of the game” with the Russians. For example, discussing the security situation on the Korean peninsula, using ties with Moscow to restrain Pyongyang, or seeking agreements on energy supplies.

The opening of closer dialogue between Seoul and Moscow poses a threat to Ukraine. Any expansion of economic or political contacts—as investment or trade in technology—effectively gives Russia new ways to evade sanctions. In 2014, Seoul already tried to use Russia's isolation at the time to increase investment and gain access to Russian energy resources. Today, similar opportunities may arise in the fields of semiconductors, maritime transport, and so on. When Seoul avoided sanctions in 2014, many warned that this would give the Kremlin ways to escape Western restrictions. Involving Russia in “supporting” security in the region raises Moscow's geopolitical status, even though the Kremlin itself has strengthened North Korea's military capabilities through strategic cooperation, which has worsened the security environment around South Korea.

Thus, Lee Jae-Myung's government is trying, on the one hand, to maintain a coalition of democracies in the region and, on the other hand, to prevent escalation on its own border, where Russia is involved through North Korea. Pyongyang and Moscow have shown that they are determined to go all the way against the West. Therefore, the key question is how successful the policy of the new president, Lee Jae-Myung, can be with those who do not want peace but can use the peaceful aspirations of others to obtain concessions. After all, just as Russia is doing now, under the “smokescreen” of interest in peace, it continues its war against Ukraine, trying to destroy its statehood. Peace must be based on strength—the only thing that dictatorships, as North Korea and Russia , understand. South Korea must be prepared for threats from its northern neighbor and support the democracies that are already confronting Pyongyang and Moscow on the battlefield.

Analytical article prepared by Kateryna Vodzinska, expert at the Resurgam think tank on Southeast Asia and China.