Japan alarm over N Korea reactor

The Yongbyon reactor has been at the centre of the nuclear row

Japan has added its voice to growing concerns over the reported closure of a North Korean nuclear reactor.

Analysts say the shutdown could allow fuel to be reprocessed into weapons grade plutonium for atomic bombs.

Japan's Chief Cabinet Secretary Hiroyuki Hosoda said it was "extremely worrying" that nuclear weapons material was being produced continuously.

North Korea's deputy ambassador to the UN, Han Song-ryol, has told a US paper the Yongbyon reactor had been shut.

He told USA Today on Monday that Pyongyang planned to "increase our deterrent" against a possible US attack.

South Korea cited concern over the reported shutdown earlier this week.

It reiterated this view on Wednesday, with Foreign Minister Ban Ki-moon saying that any reprocessing activity would hurt efforts to end the nuclear standoff.

"The government is closely watching activities at the North's Yongbyon nuclear reactor, and we cannot but express serious concern should the North move toward reprocessing," he told reporters on Wednesday.

"Such activity is not in the interest of the North, and goes against the expectations of the international community," he said.

Ongoing standoff

North Korea has claimed before to have reprocessed fuel rods from the Yongbyon reactor to make weapons-grade plutonium.

In 2003, the North said it had reprocessed 8,000 fuel rods - enough to make a handful of nuclear weapons - although the claim has not been independently verified.

South Korea reported the reactor's closure earlier this week

Tensions over the North Korean nuclear standoff appear to be on the rise.

In February it admitted publicly for the first time that it possessed nuclear weapons, and also said it would not return to multi-lateral talks unless the US changed its "hostile" attitude towards Pyongyang.

Since 2002, three rounds of discussions involving the US, Russia, the two Koreas, Japan and China have sought to ease tensions on the peninsula, with little success.

But despite the standoff, South Korea continues to argue against referring the matter to the UN Security Council - a move which the US said it might consider earlier this week.

Foreign Minister Mr Ban said on Tuesday that efforts to resolve the impasse still rested with six-party negotiations.

If the matter is referred to the UN, the Security Council might consider imposing economic sanctions against North Korea - a move Seoul is eager to avoid.