The recently signed mutual defense treaty could be used to justify thewidening of the war in Ukraine, as the U.S. says North Korean and Russian troops are already battling Ukrainian forces.

South Korean and US intelligence services have confirmed the participation of North Korean soldiers in hostilities in Russia, particularly in Kursk Oblast. Source: ISW Details: South Korea's National Intelligence Service reported on 13 November that North Korean troops were participating in hostilities in Russia,

The U.S. says there will be a "firm response" as Ukrainian forces holding ground in Russia's Kursk region now face North Korean troops "engaging in combat."