North Korean troops have not been seen on the frontlines in Russia’s Kursk region for several weeks, a Ukrainian military official said Friday, amid reports of mass casualties among Pyongyang’s forces.

North Korean forces have been pulled off the frontlines in the Kursk region after suffering heavy losses in combat, The New York Times reports. According to Ukrainian and US officials, North Korean soldiers who had been fighting alongside Russian forces against Ukraine were withdrawn after sustaining significant casualties.

Ukrainian special forces tell the BBC they have not seen any North Koreans in Russia's Kursk region in three weeks.