Vladimir Putin
Vladimir PutinReuters

Russian President Vladimir Putin told North Korean leader Kim Jong Un that the two countries will "expand the comprehensive and constructive bilateral relations with common efforts," Reuters reported, citing Pyongyang's state media.

In a letter sent to Kim in honor for Korea's liberation day, Putin said closer ties would be in both countries' interests, and would help strengthen the security and stability of the Korean peninsula and the Northeastern Asian region, North Korea's KCNA news agency said.

Kim also sent a letter to Putin saying Russian-North Korean friendship had been forged in World War II with victory over Japan, which had occupied the Korean peninsula.

The "strategic and tactical cooperation, support and solidarity" between the two countries has since reached a new level is their common efforts to frustrate threats and provocations from hostile military forces, Kim said in the letter.

KCNA did not identify the hostile forces, but it has typically used that term to refer to the United States and its allies.

The letter from Putin to Kim comes amid tensions between the US and North Korea.

North Korea has conducted more than a dozen weapons tests since January, including the firing an intercontinental ballistic missile at full range for the first time since 2017.

North Korea has ramped up its missile tests ever since talks with Washington on denuclearization failed.

Former US President Donald Trump tried to reach an agreement with North Korea while in office. Kim and Trump met in Hanoi in 2019 for a summit that left nuclear talks at a standstill.

The pair had met three times since June 2018 but made little progress towards denuclearization.

The Biden administration reached out to North Korea shortly after taking office, but the country did not respond to those overtures.

The Biden administration says it is ready to start talks with North Korea without preconditions, but would pursue working-level negotiations and not the pageantry of another summit.

Kim recently said his country is ready to mobilize its nuclear war deterrent and for any military clash with the United States.