Moscow, March 31 (RHC-Xinhua) -- Russia said on Monday it was concerned about the renewed tension on the Korean Peninsula, as the Democratic People's Republic of Korea (DPRK) and South Korea reportedly traded artillery fires near their disputed western maritime border.

Moscow also expressed concerns over the tough rhetoric from both Seoul and Pyongyang, the Russian Foreign Ministry said in a statement.

On Sunday, the Democratic People's Republic of Korea vowed "not to rule out a new form of nuclear test" in response to an earlier UN Security Council statement, condemning its recent ballistic missile launches.

The Democratic People's Republic of Korea began a live-fire drill Monday near the disputed western maritime border with South Korea. The South Korean Defense Ministry said its military fired back after Democratic People's Republic of Korea artillery shells fell south of the western sea border.

Russia urged both Korean sides to exercise restraint, and blamed joint South Korea-U.S. military exercises for the recent escalation of tension.

"It is impossible not to see that periodical worsening of the situation in the region coincides with annual large-scale military drills of the United States and South Korea," the statement said.

It added: "excessive military activity" in Northeastern Asia with strategic bomber missions and airborne troops operations contained "provoking elements."