Russia's foreign ministry on Wednesday criticized South Korea's decision to impose sanctions on Russian ships and others, and vowed to take actions in response to the "unfriendly step."

On Tuesday, South Korea imposed sanctions on two Russian individuals and their companies involved in the illegal sending of North Korean IT workers overseas as well as two Russian vessels involved in shipping containers of military supplies between Pyongyang and Moscow.

"The introduction of illegitimate sanctions will have negative consequences for relations with Russia," Russian Foreign Ministry spokesperson Maria Zakharova said during a briefing.

Zakharova said Russia will respond to the South Korean government's "unfriendly step," without elaborating.

Seoul's latest sanctions came after the UN Security Council failed to extend the mandate of the Panel of Experts monitoring sanctions on North Korea by another year due to Russia's veto. The panel's mandate had been extended annually since it was launched in 2009. (Yonhap)