North Korea is believed to have increased the scope of submarine exercises conducted close to a disputed sea boundary line with the South, Agence France-Presse reported on Thursday (see GSN, April 7).

A South Korean defense official told the JoongAng Ilbo that since March, North Korea had been conducting submarine drills encompassing five to six vessels at its Bipagot base.

“It’s highly unusual for them to beef up submarine drills in March so we’re intensely monitoring the situation,” the unidentified official said.

Seoul believes a North Korean submarine-launched torpedo was behind the March 2010 sinking of the warship Cheonan, an incident that killed 46 South Korean sailors. Pyongyang continues to claim innocence.

The North has also begun to relocate hovercraft to a new boundary-area naval site that is expected to be finished in June, a separate source told the South Korean newspaper. The new outpost would enable North Korean military personnel to invade South Korean islands by hovercraft inside of 30 minutes, the report said.

South Korean Defense Minister Kim Kwan-jin on Tuesday warned that the Stalinist state could launch new sneak strikes from across the maritime boundary line (Agence France-Presse I/Google News, April 7).

The defense chief on Thursday said the North might mount a terrorist assault on urban population centers in the South, the Yonhap News Agency reported. Pyongyang might seek to exploit security weaknesses in the centers of South Korean cities, Kim said to parliament members.

The last such attack against the South occurred in 1968.

Kim also said South Korean armed forces conduct routine drills in four localities that house atomic energy facilities. Further specifics were not provided (Yonhap News Agency I/Korea Herald, April 7).

Meanwhile, the presumed successor to ailing North Korean dictator Kim Jong Il on Thursday did not receive a parliamentary appointment to the National Defense Commission as many international observers had expected, Yonhap reported.

That the Supreme People’s Assembly apparently ended its session without elevating Kim Jong Un to the country’s most powerful decision-making body does not necessarily signify there are problems in the transfer of power from father to son, Dongguk University professor Kim Yong-hyun said.

“The North appears to moderate its pace in handing over the power,” Kim said (Yonhap News Agency II, April 8).

Some experts believe that preparations for Kim Jong Un to succeed his father will be finished no later than next year, the Korea Times reported.

Sejong Institute researcher Hong Hyun-ik said the fact that there was no announcement regarding a promotion for the younger Kim demonstrates that his father is not worried about a premature death and is not in a rush to pass on power (Kang Hyun-kyung, Korea Times, April 7).

Elsewhere, Pyongyang’s representative to the stalled six-party nuclear talks traveled to Beijing at the same time as U.S. Assistant Secretary of State Kurt Campbell was meeting with Chinese officials there, Yonhap reported

First Vice Foreign Minister Kim Kye Gwan and Campbell are anticipated to meet separately with China’s envoy to the nuclear talks, Wu Dawei.

The six nation aid-for-denuclearization negotiations were last held in December 2008. The talks involve China, Japan, both Koreas, Russia and the United States. Pyongyang and Beijing have been seeking a return to talks for some time but Washington and its partners have refused to participate in new negotiations until inter-Korean relations improve and North Korea demonstrates a serious intent to permanently surrender its nuclear weapons initiative (Yonhap News Agency II).

Separately, a high-ranking South Korean official on Friday minimized the extent of progress achieved by the North in building a claimed light-water nuclear reactor at the Yongbyon nuclear complex, Yonhap reported.

“It doesn’t seem that another light-water reactor is being built,” the anonymous official told reporters.

A satellite photograph captured on March 24 and detailed by a South Korean broadcaster on Thursday revealed that new building efforts had begun not far from a 130-foot-tall structure that Pyongyang asserts is a light-water reactor.

U.S. nuclear weapons expert Siegfried Hecker viewed the structure in November when he was given a tour of the complex by North Korean officials. The structure was then only roughly 3 feet high.

North Korea asserts it intends to generate civilian nuclear power from the reactor, which is to be fueled with enriched uranium produced at a nearby facility. Uranium enrichment can also be used to produce nuclear-weapon material.

“In terms of quality, there doesn’t seem to be much progress,” the government official said. “But there do appear to be two turbine generators (in total) used to power the light-water reactor” (Sam Kim, Yonhap News Agency III, April 8).

In February, former South Korean Foreign Minister Yu Myung-hwan said the reactor project had elicited “serious concerns” from regional nations and that the matter should be given precedence to worries about North Korea’s nuclear weapons development (Agence France-Presse II/Google News, April 8).