North Korea began sending an estimated 11,000 troops to the Russian Kursk region late last year, soon after North Korean leader Kim Jong-un and Russian President Vladimir Putin agreed on a mutual defense pact designed to strengthen their alliance against what they called a US-led “Western hegemony.”

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 soldiers sent to fight in Russia's Kursk region haven't been seen for several weeks, reports say.