North Korean leader Kim Jong-un has discussed the "importance and necessity" of military cooperation with Russia's Vice Defence Minister, state media reported Friday, amid Pyongyang's deepening military alignment with Moscow.

Kim met with a Russian military delegation, headed by Aleksey Krivoruchko in Pyongyang on Thursday, according to the Korean Central News Agency (KCNA).

He has become the first known ranking Russian military official to visit North Korea since Russian President Vladimir Putin made his first trip to Pyongyang in 24 years for summit talks with the North's leader last month, Yonhap news agency reported.

"The talk shared recognition of the importance and necessity of the military cooperation between the two countries to defend mutual security interests," the KCNA said.

Kim also expressed his firm support and solidarity for Russia's war with Ukraine and stressed the need for the militaries of the two countries to "get united more firmly" to develop bilateral relations, according to the KCNA.

The latest visit by Krivoruchko appears to be a follow-up to the Kim-Putin summit.

After the talks, Kim and Putin signed a new partnership treaty that calls for the two nations to offer military assistance "without delay" if either comes under attack.

North Korea has been accused of supplying artillery rounds and munitions to Russia for use in the war in Ukraine in return for Moscow's suspected transfer of high-tech weapons technology. Both nations have denied such arms deals.

But following the summit talks, North Korea seems to be no longer concealing its military ties with Russia, given that Kim explicitly mentioned "military cooperation" between the two nations.