This military partnership with Moscow has been invaluable for Kim Jong-un’s regime, Maj Gen Vadym Skibitskyi, deputy head of Ukraine’s military intelligence agency, the HUR, told the Guardian.

“North Korea’s armed forces got new ammunition [from Russia]. Its soldiers gained experience of modern conflict. No other army in the region – Japan, South Korea and other countries – [has] participated in a modern war between two huge regular armies.”

The ideological commitment of their forces became clear when Ukraine captured two wounded North Korean prisoners in January.

“We were shocked by them. They were bio-robots. They tried to kill themselves by biting their own veins,” Skibitskyi says. When one was asked if he wanted to return home, he replied: “Yes, because I will be treated like a hero. I fought in a modern war.”

North Korean troops are learning about combined arms warfare and the operation of strike and reconnaissance drones, electronic warfare systems, and other technologies previously unfamiliar to them.

Moscow has transferred advanced weaponry and has helped upgrade the accuracy of North Korea’s KN-23 ballistic missiles, which have since targeted Ukrainian urban centres, including Kharkiv.

In June, the Ukrainian president, Volodymyr Zelenskyy, issued a pointed warning identifying South Korea directly: “This must be addressed now, not when thousands of upgraded Shahed drones and ballistic missiles begin to threaten Seoul and Tokyo.”

However, a mix of strategic, economic and political factors are discouraging more visible action from South Korea, says Dr Yang Uk, a defence expert at the Asan Institute for Policy Studies in Seoul.

Acknowledging North Korea’s military experience as a direct threat to Seoul would create pressure for a more robust domestic response, including potential weapons transfers to Ukraine that remain deeply unpopular in South Korea.

“Defence officials are particularly wary after December’s events,” Yang said, referring to the failed declaration of martial law by South Korean’s then president, Yoon Suk Yeol. “They’re really afraid of political attack and prefer to stay unseen by the public and press.”

Yang warns that Russia is working to integrate North Korea into its long-term defence supply chain – a partnership that could reshape Asia’s military balance long after the war ends.

Some analysts see Seoul’s silence as an extension of its longstanding “strategic ambiguity”: a reluctance to engage in foreign conflicts or unnecessarily alienate key powers, particularly those that might retain influence over Pyongyang.

Economic factors weigh heavily too. Prewar, Russia was one of South Korea’s top trading partners. Amid Donald Trump’s tariff threats, the new Lee Jae Myung government’s focus on economic recovery and “pragmatic diplomacy” leaves little appetite for confrontation.

Domestic politics also play a role. Lee’s Democratic party supports engagement with the North, reflecting how South Korea’s left-right divide centres more on North Korea policy than on western progressive values. Voices on the left argue South Korea owes Ukraine nothing.

Old norms and modern threats

Some of Seoul’s inertia may be bureaucratic. Chun points to procurement and planning processes that can take years, even as threats evolve within months.

“We are dealing with a level 10 super Godzilla,” he said. “But the bureaucracy only sees a tiger.”

North Koreans are already employing what they have learned in battle, he warns. “This should be a real wake-up call.”

Skibitskyi echoes that concern, suggesting South Korea’s military doctrine is outdated and modelled on a pre-drone era.

When asked by the Guardian whether it viewed North Korea’s deployments and combat experience in Ukraine as a security concern, South Korea’s defence ministry avoided addressing the implications directly.

“The participation of North Korean military personnel in the war in Ukraine constitutes a flagrant violation of the UN charter and relevant UN security council resolutions,” a spokesperson said. “The Republic of Korea strongly condemns such inhumane and unlawful acts in concert with the international community.”

Whether Seoul’s cautious approach reflects calculated long-term strategy or institutional paralysis remains unclear.

But for Chun, the warning signs are impossible to ignore.

“This is like a speeding train coming towards you,” he said. “You better move aside or start making preparations – while you still have time.”