North Korean Foreign Minister Choe Son-hui has sent a congratulatory message to her Russian counterpart over Moscow's key national holiday and vowed stronger cooperation between the two nations, state media reported Tuesday.

In the message sent to Russian Foreign Minister Sergey Lavrov on Monday on the occasion of Russia Day, Choe said Pyongyang and Moscow have ushered in a new "heyday" in their friendly relationship, according to the Korean Central News Agency.

"Mutual cooperation and support in terms of bilateral and international affairs have become stronger than at any time," Choe was quoted as saying by the KCNA.

She also voiced confidence that the two nations will build stronger "strategic and tactical cooperation" in the diplomacy field for the development of the bilateral ties, according to the KCNA.

North Korea has expressed its support of Russia despite international condemnation over Moscow's war with Ukraine, amid allegations that Pyongyang has provided arms to Moscow for use in the war.

In North Korean leader Kim Jong-un's congratulatory message to Russian President Vladimir Putin over the holiday, he voiced his willingness to build closer ties with Russia by "holding hands firmly with Putin."

Russia Day is celebrated on June 12 to mark the adoption of the Declaration of State Sovereignty of the Russian Soviet Federative Socialist Republic in 1990. (Yonhap)