Questions abound about the combat quality of Pyongyang’s troops, but they could bail out Moscow and end up alarming Seoul.

The U.S. defense secretary said Wednesday there is evidence that North Korea has sent troops to Russia, calling it a “very, very serious issue” if they join the war in Ukraine on Moscow's side and warning of possible consequences.

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.