North Korean leader Kim Jong-un, right, and Russian President Vladimir Putin walk side by side in a garden in Pyongyang following the signing of a comprehensive strategic partnership treaty, in this photo published by the Korean Central News Agency, June 20. Yonhap

North Korean leader Kim Jong-un has sent a New Year's letter to Russian President Vladimir Putin, vowing to further solidify bilateral military cooperation, the North's state media reported Tuesday.

"The New Year 2025 will be recorded as the first year of war victory in the 21st century when the Russian army and people defeat neo-Nazism and achieve a great victory," Kim said in the letter sent to Putin the previous day, according to the Korean Central News Agency (KCNA).

The KCNA said the letter, on behalf of Kim, the Korean people and the country's entire armed forces, conveyed "warm greetings of best wishes to the fraternal Russian people and all the service personnel of the brave Russian army."

Kim expressed a willingness to further strengthen his country's "comprehensive strategic partnership" with Russia by devising new projects and implementing them strongly to build strong nations and achieve peace and prosperity for their peoples, the KCNA reported.

Kim "wished Vladimir Putin greater success in his responsible and heavy state leadership activities and the Russian people prosperity, wellbeing and happiness," the report said.

The letter came amid deepening military, economic and other ties between Pyongyang and Moscow, following the signing of a mutual defense treaty by Kim and Putin during the Russian president's visit to the North Korean capital in June.

North Korea has deployed more than 10,000 troops to support Russia in its war against Ukraine, with South Korean officials warning that the North is preparing to send more troops and supply more military equipment to Moscow. (Yonhap)