Ukrainian media say Russia's military has created a battalion of up to 3,000 North Korean soldiers.

The media reported this on Tuesday, quoting intelligence service sources.

They said the battalion may join fighting in Russia's western region of Kursk, where Ukrainian forces are conducting cross-border attacks.

The reports also said North Korean troops have been confirmed in the Kursk and Bryansk regions.

They said 18 North Korean soldiers have already deserted 7 kilometers from the border with Ukraine.

The US-based Institute for the Study of War said on Tuesday that it cannot confirm the reports. The ISW argued that Russian President Vladimir Putin wants to avoid domestic ramifications from mobilizing Russians. It added that Putin appears more willing to absorb North Korean personnel into Russia's military.

Ukrainian President Volodymyr Zelenskyy says Russia and North Korea are further stepping up their military cooperation. He has accused the North of providing weapons and military personnel to Russia.