Satellite imagery of the Najin port taken from October to December shows a steady stream of ships at the facility, hundreds of shipping containers being loaded and unloaded, and rail cars ready to transport goods.

The activity appears to have picked up since early October, when the US accused North Korea of sending munitions to Russia. The White House provided imagery it said showed weapons later being delivered thousands of miles away to a depot in the Russian town of Tikhoretsk for use in Ukraine.

The flow of munitions that the US and South Korea say have included hundreds of thousands of artillery shells could grow far greater in importance as divisions in the US Congress and European Union over military aid threaten Kyiv’s ability to repel Russian President Vladimir Putin’s invasion.

“Pyongyang’s decision to deliver munitions at scale once again underscores the grave threat that North Korea poses to international security, this time feeding a conflagration on European soil that has already cost the lives of tens of thousands of Ukrainians and consumed tens of billions of dollars in Western military support,” according to a report by the Royal United Services Institute, a UK security think tank.

Pyongyang, which has been banned from arms sales for about 15 years, has repeatedly rejected accusations it is supplying Russia.

Analysis of the satellite data suggests otherwise. In a recent example, an image from Dec. 9 seems to show the Russian container ship Angara, sanctioned by the US, in Najin’s port unloading cargo while containers from North Korea await loading at an adjacent pier.

“Satellite imagery shows that round trips of cargo vessels between Najin, North Korea, and Dunay, Russia, have continued unabatedly despite additional US sanctions and widespread reporting on this activity in the past few months,” said Jaewoo Shin, an analyst at the Open Nuclear Network in Vienna.

Shin said that while the nature of the cargo can’t be confirmed with available imagery, the number of round trips and transferred containers suggest a significant and ongoing exchange, possibly including weapons and other military supplies.

As the North Korea-Russia trade picks up, the flow of US military aid to Kyiv has been increasingly under threat, with the Pentagon saying it will run out of money to replace weapons sent to Ukraine by Dec. 30 unless Congress approves additional funding. That’s unlikely now, with most lawmakers out of Washington for the year-end holidays.

With an effective stalemate on the battlefield, the Kremlin is increasingly confident Russia can consolidate its control over occupied regions of eastern and southern Ukraine and wait for international support for Ukraine to erode. Putin said this month that “there’ll be peace when we achieve our goals.”

For many US partners, the flagging support for Ukraine is tied in part to a much-vaunted counteroffensive during the spring and summer that failed to deliver on the high expectations of allies.

While satellite imagery shows steady activity at Najin, the vessels docking there appear to have turned off international maritime transponders that give their location, effectively turning them into ghost ships as they make the relatively short trip between Najin and Dunay — also written as Dunai — about 180 kilometers (110 miles) away. The Central Intelligence Agency identified the port as a Soviet submarine base during the Cold War, according to a document obtained by RUSI, the UK think tank.

RUSI’s October report analyzed dozens of high-resolution images that it concluded showed a few cargo vessels repeatedly making the trip between Najin and Dunay, likely packed with North Korean arms that are then sent across Russia.

That trade appears to have continued in the time since the report was published, according to Joseph Byrne, a research fellow at RUSI and co-author of the report.

“There has been a continuation of deliveries by these vessels,” he said, adding there is “a continuation of the unloading of boxes loaded in Russia and delivered to North Korea and then the loading of containers that have seemingly comes down from rail cars from other places in North Korea to apparently be shipped back to Russian military facilities.”

South Korea’s National Intelligence Service told lawmakers in November there had been about 10 shipments of weapons from North Korea to Russia since August, likely encompassing more than 1 million rounds of artillery. North Korea holds some of the world’s largest stores of munitions, much of it interoperable with weapons Russia has on the front lines.

“About six weeks later, I’ve seen no signs of the transfer rate slowing down — so for all we know that’s another half million shells,” said weapons expert Joost Oliemans, who co-authored the book The Armed Forces of North Korea.

Oliemans said he’s identified four types of munitions that have been a part of recent deliveries: 120 millimeter mortars, 122mm and 152 mm artillery shells and 122 mm rockets based on an analysis of what is making its way to the front lines.

“The situation on the battlefield is impacted” by those deliveries, he said. “Rather than seeing a notable change in tactics or swaths of land suddenly changing hands, it will allow Russia to keep up much higher pressure for longer on Ukrainian forces.”

An extra one million shells means about 2,700 rounds more per day Russia could fire at Ukraine, which is already having trouble procuring artillery and may face more difficulty if aid from the US isn’t secured.

“How much exactly North Korea will be able to deliver is anyone’s guess,” Oliemans said, adding that deliveries will likely slow down once inventories become depleted, with North Korea’s manufacturing capabilities insufficient to keep up with the pace of demand.

Russia’s importance to North Korea had waned after the end of the Cold War, with China becoming Pyongyang’s biggest benefactor. Trade between Russia and North Korea slowed to a trickle when Kim shut the borders at the start of the pandemic.

But as Covid protections eased, and international sanctions hung over Moscow and Pyongyang, the two rekindled ties, finding they each had something the other wanted and could trade without real repercussions from the outside world.

The assistance Kim receives from Russia is easing the pressure of years of sanctions over his increasing nuclear arsenal and potentially making the already-tense situation on the Korean Peninsula worse.

“With both Kim and Putin recognizing the utility and benefits of partnership, cooperation is likely to continue between North Korea and Russia into next year,” said Soo Kim, a former Korea analyst at the Central Intelligence Agency, who now works at US-based management consulting firm LMI. 

“The give-and-take between the two countries is unlikely to be stopped so long as the international consequences — sanctions, reputational shaming — remain symbolic and largely insufficient to deter bad behavior,” she said.