After a battle in Russia's snowy western region of Kursk this week, Ukrainian special forces scoured the bodies of more than a dozen slain North Korean enemy soldiers. Among them, they found one still alive.

Russia has leaned on its increasingly close ally North Korea for supplies of artillery shells and ballistic missiles to prosecute a grinding war in Ukraine. In October, the partnership entered a new phase as Pyongyang dispatched thousands of soldiers to bolster Russia’s armed forces.