SEOUL - The Republic of Korea's military on Monday staged its maritime firing exercises in northwestern islands near the sea boundary with the Democratic People's Republic of Korea (DPRK), Yonhap news agency reported citing a military official.

The official was quoted as saying that the military began the live-fire exercises from 4 pm local time (0700GMT) with its K-9 self-propelled artilleries in islands of Yeonpyeong and Baengnyeong.

Whether the firing drill is finished has yet to be confirmed.

The artilleries of the ROK?faced south for the firing exercises, with only K-9 self-propelled guns mobilized.

The military originally planned to mobilize Spike missiles and 130-mm multiple rocket launchers for the firing drill, but the worsening weather conditions from a heavy sea fog led to the reduced mobilization.

The firing drill was carried out to mark the fifth anniversary of the DPRK's shelling of the?ROK's island of Yeonpyeong.

Five years ago, the DPRK shelled the Yeonpyeong, one of the five border islands of the ROK?near the west sea boundary, killing two civilians and two marines.

The DPRK's Southwest Front Command of the Korean People's Army (KPA) said in a statement Sunday that if the?ROK military pushes ahead with the firing drill, it will make ruthless retaliations against the five islands.

There has been no specific movement found from the DPRK forces yet, according to the military official.