President Vladimir Putin, asked about reports that North Korea had sent thousands of troops to Russia, said on Thursday that it was Moscow's business how to implement a partnership treaty with Pyongyang.

The first group of North Korean troops have been sent to the Russian region of Kursk where some have tried to desert, according to reports. Ukraine launched an incursion into the Russian region on August 6 and Putin is said to be planning to use the North Korean soldiers in his fight to recapture territory.

Russian lawmakers have ratified a pact with North Korea envisioning mutual military assistance, a move that comes even as the U.S. confirmed the deployment of 3,000 North Korean troops to Russia.