Ukrainian President Volodymyr Zelensky said during his Friday evening address: "New assaults took place in the areas of the Kursk operation—the Russian army with North Korean soldiers brought in again. A significant number of occupiers have been eliminated, we're talking hundreds of Russian and North Korean servicemen."

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.”

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.

In December last year, over 11,000 North Korean troops had been deployed in Russia's Kursk region to aid Russian forces in foiling Ukrainian counterattacks in the ongoing Russia-Ukraine war.

North Korean soldiers previously fighting alongside Russia's army on the Kursk front line appear not to have been engaged in combat since mid-January, South Korea's spy agency told AFP on Tuesday, after Ukraine claimed they had been withdrawn following heavy losses.

A military source, who requested anonymity to discuss sensitive information, described a marked improvement in the precision in all the more than 20 North Korean ballistic missile

North Korean troops, largely special ops forces, have suffered high casualties in bloody assaults not unlike other units, including prison units.

"The worst problem we are facing is the one coming from North Korea," the head of Kyiv's military intelligence agency said in the fall.