Pyongyang is believed to have sent some 11,000 soldiers to help Putin’s army recapture a swathe of the Kursk region of Russia which Ukrainian forces seized in a surprise attack last summer. The Russian military has been gradually gaining ground in the attempt to force Ukrainian units out of Kursk.

North Korean troops fighting for Russia have been pulled from the front line for extra training after crude tactics led to massive casualties.

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.

Thousands of North Korean troops helped Russia regain some of its territory in the Kursk region following Ukraine's counterattack, but the Russian army is now using them less on the front line and have pulled some back.

South Korea's spy agency says that North Korean forces have suffered more than 3,000 casualties while fighting alongside Russian troops.

South Korea's National Intelligence Service has reportedly confirmed that North Korea has withdrawn its troops from the frontline in Russia's Kursk region after entering the war late last year