Russian Defence Minister Andrei Belousov (left) is seen by the guard of honour upon his arrival at an airport in Pyongyang on Nov. 29. (Yonhap)

North Korean leader Kim Jong-un has met Russia's visiting defense minister and expressed his support for Russia's war against Ukraine, state media reported Saturday, amid deepening military cooperation between the two nations.

Kim had a "friendly and trustworthy" meeting with Russian Defense Minister Andrei Belousov in Pyongyang on Friday, according to the Korean Central News Agency (KCNA).

Belousov arrived in North Korea the previous day for a visit that came as North Korea has sent thousands of its troops to Russia in support of Moscow's war against Ukraine.

In the meeting, the North's leader condemned the United States and the West for permitting Ukraine to use supplied long-range missiles for strikes against Russia, calling the move a "direct" military intervention, the KCNA said.

"It is an exercise of the right to self-defense for Russia to take resolute action to make the hostile forces pay the price," Kim said.

Kim's remark was seen as expressing support for Russia's recent firing of a hypersonic intermediate-range ballistic missile into the Ukrainian city of Dnipro.

The strike was seen as a response to the U.S. and Britain's allowing of Kyiv to strike Russian territory with advanced Western missiles.

The KCNA report did not mention whether Kim and Belousov discussed North Korea's troop deployment to Russia.

He affirmed that "the DPRK government, army and people will invariably support the policy of the Russian Federation to defend its sovereignty and territorial integrity from the imperialists' moves for hegemony," the KCNA said, using the acronym of North Korea's official name.

North Korea and Russia have been bolstering military cooperation under a major defense treaty signed in June that calls for providing military assistance "without delay" if either side comes under attack.

Earlier this month, North Korea ratified the comprehensive strategic partnership treaty through a decree signed by Kim. Russian President Vladimir Putin also signed the treaty into law after Russia's upper and lower houses ratified it.

North Korea has not publicly confirmed its troop deployment to Russia. But South Korea and the U.S. have said some of the North's deployed soldiers have already entered combat in Russia's western Kursk region.

Seoul officials are concerned that North Korea may receive advanced weapons technology from Russia in return for its troop dispatch to Moscow.

North Korea's troop deployment has raised concerns about an expansion of Russia's protracted war against Ukraine. Pyongyang has provided artillery and conventional weapons to Russia to support its war.

In regard to Belousov's visit to North Korea, experts raised the possibility of Russia asking for North Korea to further provide weapons or send troops to help bring the war to its advantage.

Ukrainian and Russian forces have intensively engaged in combat in recent weeks ahead of U.S. President-elect Donald Trump taking office in January. During the campaign, Trump said, if elected, he can end the war "in one day."

Meanwhile, Belousov held talks with his North Korean counterpart, No Kwang-chol, the previous day to discuss strengthening "strategic and tactical cooperation" between the two countries' armies by thoroughly implementing the strategic partnership, the KCNA said in a separate dispatch.

Russia's defense minister "expressed the willingness to further expand the mutually beneficial cooperation in the complicated international situation," it said.

Belousov was quoted as saying by Russia's news media Friday that Russia's cooperation with North Korea is "expanding" in various areas, including in the military field. (Yonhap)