Satellite images show how hundreds of North Korean troops were likely transported to a secluded Russian port

 

    A crane is seen extending to one of Russia’s naval landing ships, which researchers believe is the Nikolay Vilkov, at Dunai port on October 17, and a covered cargo truck is on the dock next to it. - James Martin Center for Nonproliferation Studies/Planet Labs PBC

Satellite imagery has revealed that hundreds of North Korean troops were likely transported by sea to Russia to fight in its war against Ukraine, according to a new analysis from a U.S.-based think tank shared exclusively with CNN.

Researchers at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies in California believe at least two Russian naval ships moved North Korean soldiers to a military port in Dunai, in Russia’s Far East, during October and November.

The South Korean National Intelligence Service (NIS) first identified these transfers, reporting last year that some soldiers were transported from North Korean port areas including Chongjin, Hamhung, and Musudan. However, at the time, the NIS only released a grainy radar image as evidence.

“I don’t think the Russians or North Koreans want these transfers caught on camera,” said Sam Lair, a research associate at the Center for Nonproliferation Studies. “The level of secrecy is quite remarkable.”

Now, researchers have verified that the Russian vessels identified by South Korean intelligence docked at Dunai during the same period as the reported troop transfers.

In North Korea, soldiers likely boarded the ships at night, making it difficult to capture direct evidence of their movement. However, satellite images of Dunai suggest that the Russians have been less cautious there.

One such image from Planet Labs shows a crane extended toward a Russian naval landing ship—believed to be the Nikolay Vilkov—at Dunai port on October 17, with a covered cargo truck positioned nearby. By October 20, the crane had been retracted, suggesting that a troop transfer had taken place.

Researchers identified the Russian “Ropucha-class” and “Alligator-class” landing ships in the satellite images by comparing them with photos taken by the Japanese Defense Ministry in March 2022, when the vessels passed through Japanese waters. Each of these ships can reportedly carry several hundred troops, potentially up to 400.

Dunai’s remote location makes it an ideal site for discreet operations, Lair explained. Unlike Vladivostok, a major port with a civilian presence, Dunai is a secure military facility where movements are less likely to be noticed.

“This is an isolated place where they can carry out these transfers without attracting attention—not just from their citizens, but also from intelligence agencies,” Lair said.

In January, Ukrainian officials and Western intelligence estimated that approximately 12,000 North Korean soldiers had been sent to Russia, with around 4,000 killed or injured. Kyiv claims to have captured at least two North Korean troops. Neither Moscow nor Pyongyang has confirmed the presence of North Korean soldiers on the front lines.

CNN has reached out to the Russian Ministry of Defense for comment.

North Korean troops have reportedly been stationed in the Russian region of Kursk since late October, tasked with repelling Ukrainian incursions.

“The Russians have been very careful to limit exposure of the North Korean troops, moving them directly to military training facilities,” Lair wrote in his analysis. While the exact reason for the secrecy remains unclear, using Dunai for some of these transfers would align with that strategy.

Dunai has previously been used for cargo exchanges between Russia and North Korea since Pyongyang began supporting Moscow’s invasion of Ukraine in 2023, according to the James Martin Center for Nonproliferation Studies.

Satellite images from October show a cargo ship being loaded at North Korea’s Rajin port and docking at Dunai two days later.

A report published in October 2023 by the UK-based Royal United Services Institute for Defence and Security Studies (RUSI) stated that “Russia has likely begun shipping North Korean munitions at scale” to the “inconspicuous naval facility” in Dunai.

“We spend a lot of time monitoring North Korea because of its nuclear weapons program, conventional weapons, and missile development,” Lair said. “We’ve been tracking the North Korea-Russia connection since it began, in part because we suspect this relationship may be a two-way exchange.”

Alyona Getmanchuk, director of the New Europe Center think tank in Kyiv, recently told a forum in South Korea that North Korea is gaining critical combat experience in Ukraine.

“This isn’t just about supplying missiles—it’s about testing them in real battlefield conditions,” Getmanchuk said during an event at the Goethe Institute in Seoul.

She added that North Korea has used these experiences to refine its missiles for greater accuracy, while its ground troops are also improving.

“They arrived completely unprepared,” she said. “But now they’re learning fast, adapting their tactics to modern, high-tech warfare.”

Lair noted that the relationship between Pyongyang and Moscow has deepened significantly since the war began. “Sending your soldiers to fight in another country’s war is a strong indicator of how close this partnership has become,” he said.

There are signs that Russia and North Korea may no longer be using sea routes for troop movements. Instead, South Korean intelligence has reported frequent Russian military flights between Vladivostok and Pyongyang.