Zelensky has claimed that some 11,000 North Korean troops are in the region. They are said to be in Belgorod as well, which has also been subject of frequent Ukrainian cross-border attacks.
The CNN report continues, "Separately, a Ukrainian commander told CNN Sunday that North Korean troops were taking part in direct combat operations in Kursk, as well as defensive operations in the neighboring Belgorod region of Russia and in Russian-occupied Ukrainian territories."
Starting last week, Zelensky said there have been direct and deadly clashes between Ukrainian and North Korean forces. Russia has not completely denied it, saying that a defense treaty inked between Moscow and Pyongyang allows for allied forces to help defend Russian territory.