North Korean soldiers fighting alongside Russian forces in Kursk Oblast are already "legitimate targets" for the Ukrainian military, U.S. State Department Spokesperson Matthew Miller said on Dec. 16.
The remarks came the same day that the Pentagon confirmed the first North Korean casualties in Russia's war against Ukraine.
"North Korean soldiers who were deployed to Kursk are already legitimate targets," Miller told reporters during a press briefing.
"They entered a war, and they are, as such, combatants and are legitimate targets for the Ukrainian military. We have seen North Korean soldiers who have been killed in action on the battlefield inside Russia."
Miller warned that if North Korean personnel crossed the border from Russia into Ukraine and engaged in combat, the U.S. would consider it a significant escalation in the war.
"And if they were to cross the border into Ukraine, that would be yet another escalation by the Government of Russia and also an escalation by the Government of North Korea ... That would absolutely be an escalation," he said.
Miller declined to say what the U.S. response would be to such an escalation by Moscow and Pyongyang.
"I'm not going to preview that publicly," he said.
President Volodymyr Zelensky reported on Dec. 14 that North Koreans had begun engaging in assault operations with Russian troops fighting aginst Ukraine in Kursk Oblast. Ukraine and the U.S. had sounded the alarm on the deployment of North Korean soldiers in the region for months prior.
Ukraine's military intelligence agency (HUR) said on Dec. 16 that at least 30 North Korean personnel had been killed or wounded in assaults in Kursk. Zelensky then alleged that Russia has gone to great lengths to hide North Korean losses, including burning soldiers' bodies.
Thus far, North Korean units have only been deployed in Kursk Oblast, the Russian border region that Ukrainian troops attacked in a shock offensive in August. North Korean troops have not yet engaged in combat on the Ukrainian side of the border.
Russia and North Korea have deepened their economic and military ties since the full-scale invasion of February 2022. The two nations signed a defense treaty in June, requiring either state to render military aid to the other in the event of an attack.