A third of the troops North Korea deployed to western Russia’s Kursk Oblast late last year has been killed or wounded, according to Ukrainian Pres. Volodymyr Zelensky. Col. Ants Kiviselg, the head of the Estonian defense forces’ intelligence center, confirmed the claim.

The soldiers appear to have been pulled back from the front lines in Kursk after suffering heavy casualties during barely a month of combat, Ukrainian officials said.