This image, captured from a video posted on X by the Centre for Strategic Communication and Information Security of Ukraine, shows what appears to be North Korean soldiers receiving apparent Russian gear, Oct. 18. Yonhap

A group of North Korean soldiers disguised as "indigenous people" of Russia's Far East have engaged in combat with Ukrainian troops in Russia's western border region of Kursk, according to a Ukraine news report.

Citing Kyiv's top military officer, RBC Ukraine on Sunday (local time) reported that more than 11,000 North Korean soldiers are already stationed in the Kursk region and have take part in battles against Ukrainian troops.

"These are mostly general military units. They are disguised as indigenous people of the Far East. They have the appropriate documents," Anatolii Barhylevych, the chief of the General Staff of the Armed Forces of Ukraine, was quoted as saying.

"They are trained to conduct operations in the European part," he said.

The report came amid growing security concerns over military cooperation between North Korea and Russia, with South Korea and U.S. officials confirming that the North has sent more than 10,000 troops to Russia in support of its invasion against Ukraine.

Last week, Seoul's spy agency said North Korean troops are believed to have been assigned to Moscow's airborne brigade and marine corps, with some of them already entering combat following local adjustment training.

The National Intelligence Service (NIS) also said that North Korean troops, having entered combat, may have suffered casualties or wounds, adding that efforts are under way to determine the details of the combat circumstances and the extent of the damage.

On Sunday, the NIS said that it is closely looking into intelligence that casualties have occurred among North Korean troops in its first confirmation of such a development.

RBC Ukraine earlier reported that about 500 North Korean soldiers were killed "as a result of the Storm Shadow missile strike on the Kursk region," citing Global Defense, a defense news publisher. (Yonhap)