Russian leader Vladimir Putin asserted that his country will expand its “comprehensive and constructive bilateral relationship” with North Korea in a letter to Kim Jong Un, DPRK state media reported Monday, weeks after Pyongyang recognized Moscow-backed breakaway republics in eastern Ukraine.

Putin added that strengthened ties will benefit “the safety and stability of the Korean peninsula and the Northeast Asian region as a whole,” exchanging letters with Kim to mark the holiday celebrating Korea’s liberation from Japanese colonial rule.