Russia's Putin does not deny North Korea troops deployment in Ukraine

President Vladimir Putin has not denied US claims that North Korea had sent troops to Russia but said that it was up to Moscow how to run its mutual defence clause with Pyongyang and accused the West of escalating the Ukraine war.

The United States said that it had seen evidence that North Korea has sent 3,000 troops to Russia for possible deployment in Ukraine, a move that could mark a significant escalation of the Ukraine war.

Asked by a reporter about satellite imagery showing North Korean troop movements on Thursday, Putin said: "Images are a serious thing. If there are images, then they reflect something."

But he said it was the West which had escalated the Ukraine crisis and said NATO officers and instructors were directly involved in the Ukraine war

"We know who is present there, from which European NATO countries, and how they carry out this work," Putin said.

The Kremlin chief specifically mentioned Article 4 of the Russian partnership deal with North Korea that deals with mutual defence.

"There is article 4. We have never doubted in the least that the North Korean leadership takes our agreements seriously. But what we do within the framework of this article is our business," Putin said.

He said that Russia's army was moving forward along all sections of the front in Ukraine, and had trapped a large number of Ukrainian troops in the Kursk region.

Ukrainian intelligence agency claims that a total of around 12,000 North Korean troops, including 500 officers and three generals, were already in Russia, and training was taking place on five military bases.