At least 30 North Korean troops, deployed to bolster Russian forces in their war on Ukraine, have been killed or wounded in Russia’s Kursk region, Ukrainian authorities said Monday, marking a significant turning point after months of speculation over what role Pyongyang’s troops might play in the war.

The United States hit North Korea and Russia on Monday with new sanctions that the Treasury Department said targeted Pyongyang's financial activities and military support to Moscow. The sanctions, which list North Korean banks,