Russian President Vladimir Putin has thanked North Korean leader Kim Jong Un for hosting him for a state visit last week, claiming relations between the two countries have reached an “unprecedentedly high level.”

But South Korean President Yoon Suk-yeol denounced the new security pact that the two leaders signed at their summit as an “anachronism” directly violating U.N. sanctions, delivering a speech on the anniversary of the DPRK invasion that started the Korean War.

In a letter published on the front page of party daily Rodong Sinmunon Tuesday, Putin said Russia is always waiting to welcome Kim as an