The Biden administration said that at least 3,000 North Korean troops are training in Russia, though it remains unclear if they’ll join the war.

Secretary of Defense Lloyd J. Austin III confirmed on Wednesday that North Korea had sent troops to Russia to join the fight against Ukraine, a major shift in Moscow’s effort to win the war. Mr. Austin called the North’s presence a “very serious” escalation that would have ramifications in both Europe and Asia.

Secretary of Defense Lloyd Austin said North Korea has deployed troops to Russia, the first senior US official to confirm the development on the record, as North Korea and Russia have forged increasingly friendly ties since Moscow’s invasion of Ukraine.