Ukrainian President Volodymyr Zelenskyy said North Koreans troops, who had disappeared from the front lines in Russia's Kursk region for several weeks, have now returned.

According to AFP and Ukrainian media on Friday, Zelenskyy, in a video address, said there have been new assaults in the Kursk operation areas and that the Russian army and North Korean soldiers have been brought in again.

The Ukrainian leader said a "significant number" of opposing troops had been "destroyed," adding the number is in several hundreds.

Citing unnamed U.S. and Ukrainian officials, The New York Times reported late last month that North Korean troops were taken off the front line due to heavy casualties, and that they could possibly return after receiving additional training.