South Korea’s spy agency says North Korea appears to have sent additional troops to Russia, after its soldiers deployed on the Russian-Ukraine fronts suffered heavy casualties.

Ukrainian troops holding positions in Kursk say the North Koreans have reappeared on the battlefield and become even more formidable foes.

North Korea appears to have deployed additional troops to support Russia in its war against Ukraine, according to South Korea’s spy agency Thursday. The National Intelligence Service stated in a message to the press that North Korean forces were redeployed to the Kursk front in early February following a roughly one-month lull.