Russian President Vladimir Putin, at the closing press conference of the BRICS summit in Kazan, commented for the first time on reports about North Korean military personnel being sent to Russia, possibly to participate in the war against Ukraine.

BBC’s Russian Service says he did not deny their presence in Russia but did not clarify the purpose of their arrival.

The question was reportedly posed by a journalist from the American NBC television company. He said that satellite images show the presence of North Korean military personnel. "What are they doing here?" the journalist asked. "And isn't this a serious escalation of the conflict?"

"It was not Russia's actions that led to the escalation," Putin responded, once again speaking about the "coup" in Ukraine in 2014. He also accused Western countries of arming the Ukrainian army and helping it fight.

Putin reminded that earlier on Thursday, the State Duma ratified the treaty on "comprehensive strategic partnership" with North Korea, signed by the Russian president in Pyongyang this summer.

The treaty involves "mutual assistance in case of aggression" against one of its participants.

"There is Article 4," Putin said, adding that Pyongyang "takes our agreements seriously."

Article 4 of the agreement states that "if one of the parties finds itself at war due to an armed attack by one or more states, the other party will immediately provide military assistance with all available means in accordance with Article 51 of the UN Charter and the laws of the DPRK and the Russian Federation."

"What we will do under this article is our business," Putin concluded, without providing any details about the deployment of North Korean military personnel in Russia or their objectives.

Some sources say North Korean (DPRK) soldiers are being trained at five military sites in the far east of Russia, and will have to pass a training course lasting several weeks before being deployed in the war against Ukraine.  The United States confirmed on October 23 that thousands of North Koreans are training in Russia alongside Kremlin troops. 

The Washington Post reported on October 11 that North Korean soldiers are supporting Russian troops on the ground, and some may have already been killed and injured,  

Politico reported yesterday that according to updated estimates from Kyiv, Pyongyang has transferred about 12,000 troops to Russia, including 500 officers and three army generals.  Earlier this week Ukrainian President Volodymyr Zelenskyy said Ukraine had already spotted North Korean army officers in the Russian-occupied territories of Ukraine’s eastern region of Donbas.