North Korea is gaining crucial military experience and equipment by sending troops to Russia, a U.S. official warned the United Nations, making the regime a growing threat to neighboring countries.

Speaking a day after Trump’s inauguration, Ukraine’s president told world leaders at Davos that Europe needs to remain united and “learn how to take care of itself.”

Russia signed a strategic partnership treaty with Iran on Friday that follows similar pacts with China and North Korea. All three countries are adversaries of the United States, and Russia has used its ties with them to help blunt the impact of Western sanctions and boost its war effort in Ukraine.

Ukraine and South Korea have said Pyongyang has deployed an estimated 10,000 to 12,000 servicemen to southern Russia to fight Ukrainian forces. More VLADIMIR SMIRNOV/POOL/AFP/Getty Images

Ukraine said it retrieved a diary from a North Korean soldier that contains a confession of stealing from his Russian comrade and battle tactics.

North Korean troops have been deployed to bolster Russian forces in the Kursk border region with Ukraine, where they are gaining battlefield experience despite initial heavy losses.

The wounded fighters were taken for questioning to Kyiv, authorities said, where they could reveal details of Pyongyang’s cooperation with Moscow.

A chance for Ukraine and Trump to set Putin back and drive a wedge between Pyongyang and Moscow.

All three countries are adversaries of the United States, and Russia has used its ties with them to help blunt the impact of Western sanctions and boost its war effort in Ukraine. Presidents Vladimir Putin and Xi Jinping met in Beijing on Feb.

North Korea is “significantly benefiting” from its troops gaining battlefield experience fighting alongside Russian forces as it makes them more capable of waging war against rivals South Korea and Japan, a US official warned the UN.

"I didn't even know who we were fighting against," the captured soldier from Pyongyang told Ukraine's Security Service.