North Korean leader Kim Jong-un and Russian President Vladimir Putin have pledged to move relations between the two countries further forward as they exchanged messages marking the 75th anniversary of diplomatic ties after a summit last month, Pyongyang's state media reported Thursday.

Kim expressed his firm belief that North Korea-Russia relations will steadily develop to a new level in the future in a letter to Putin to celebrate the anniversary, according to the Korean Central News Agency.

In the letter, Kim said he was "very satisfied" with the fact that he had "candid and comprehensive" discussions with Putin for the "multiform development" of the bilateral ties during their latest summit in Russia, the KCNA said.

Kim traveled to Russia's Far East in September for a rare summit with Putin amid concerns about a possible arms deal between the two nations.

The North's leader also hoped that Russia will be victorious in its struggle for "frustrating the imperialists' persistent hegemonic policy and moves to isolate and stifle Russia," the report said.

In his message to Kim, Putin said the summit proved that the bilateral relations are continuing to "positively develop in all aspects on the basis of the glorious traditions of the past."

He said the implementation of the summit agreements will contribute to "further expanding the constructive bilateral cooperation for improving the well-being of the peoples of the two countries and ensuring security and stability" on the Korean Peninsula and in Northeast Asia, the KCNA said.

North Korea has vowed to strengthen solidarity with countries standing against the United States and is seeking to bolster its ties with China and Russia vis-a-vis the strengthening of security cooperation among Seoul, Washington and Tokyo.

Russia, then the Soviet Union, forged diplomatic ties with North Korea on Oct. 12, 1948, recognizing the North as a state for the first time in the world.

Meanwhile, North Korea reaffirmed its support for Russia's aggression against Ukraine, describing Moscow's "military operations" as a "righteous" struggle to defend its strategic security and interests.

In a statement issued to mark the anniversary, Vice Foreign Minister Im Chon-il said Pyongyang and Moscow will closely cooperate on their united front in countering imperialists' military threats and oppression. (Yonhap)