Republic of Korea Marines' K-9 self-propelled guns take part in a military exercise on Baengnyeong Island near the disputed sea border with the Democratic People's Republic of Korea on Wednesday. ROK Marine Corps / Reuters Via Yonhap

BEIJING - The armed forces of the Democratic People's Republic of Korea (DPRK) on Thursday condemned a military exercise by the Republic of Korea near their sea border as a new provocation, threatening a "sea of fire" in Seoul if any future drill violates its territory.

Beijing on the same day asked the parties involved to ease the tension, while Chinese experts said the risk of an outbreak in hostilities was still not high at the moment.

The ROK's military conducted a large-scale military exercise on five islands and their surrounding waters in the West Sea on Wednesday, the first anniversary of an artillery bombardment of the ROK's Yeonpyeong Island by the DPRK.

According to a report issued by the Supreme Command of the DPRK army through the official KCNA news agency, Seoul's rehearsal showed it had not learned the "due lesson on the first anniversary of the shelling".

The DPRK shelled Yeonpyeong near the maritime border on Nov 23 last year, killing two ROK marines and two civilians. It said it was retaliating for an artillery drill by the ROK on the island that dropped shells into the DPRK's maritime zone.

"If it dares slander our dignity again and if our sea, airspace or land is breached by a single bullet or bombshell, the sea of fire on Yeonpyeong would spread to a sea of fire engulfing the (ROK presidential) Blue House," it said.

Moreover, the report claimed last year's fatal shelling was "a legitimate self-defensive step against the provocateurs".

Foreign Ministry spokesman Liu Weimin said on Thursday at a regular news briefing that Beijing hopes the related parties will "keep in contact and dialogue and do more to help ease the situation".

In Seoul, ROK President Lee Myung-bak said on Wednesday he believes the DPRK will one day reveal its position on the shelling on the island.

The DPRK "has not formally apologized for the incident, but I expect it to formally state its position on the matter sometime for national reconciliation", Lee said during a visit to a new military unit near the tense sea border with the DPRK.

Seoul has repeatedly demanded Pyongyang apologize for the shelling, the first peacetime attack on ROK land since the end of the 1950-1953 Korean War.

The ROK Joint Chiefs of Staff (JCS) said earlier that Wednesday's drill was meant to "demonstrate our resolve to strike back at auxiliary forces as well as the source of provocation if (the DPRK) conducts another reckless provocation".

According to the JCS, K-9 self-propelled guns, a 4,500-ton destroyer, an artillery hunting radar and KF-16 fighter jets were mobilized for the one-day exercise.

Seoul's military faced severe criticism for its perceived slow and weak response last year.

The ROK has also beefed up its armed forces on five islands near the sea border with an aim to "fortify" them, establishing the Northwest Islands Defense Command.

Piao Jianyi, an expert on Korean Peninsula studies at the Chinese Academy of Social Sciences, said the response of the DPRK was not very strong, compared with its announcements in the past.

"But if the ROK further continues similar military drills that would raise tension on the peninsula, you never know what could happen," he said, adding that the overall strategy of the ROK government is to ease tension with the DPRK.

Zhang Liangui, a professor of international strategic research at the Party School of the Central Committee of the Communist Party of China, said the possibility of conflict on the peninsula is not too high, as he believes the US and the ROK are "setting a trap", which means any excessive move by Pyongyang will provide an excuse for tougher actions, and "Pyongyang knows this quite well".

Meanwhile, Zhang was not optimistic that the Six-Party Talks can be restarted soon, as the US and the DPRK have significant differences on how to resume the talks.

"The US has demanded the DPRK give up its nuclear program, but Pyongyang has not made any response," he said.

Xinhua contributed to this story.