London, Nov. 23: Japan’s top government spokesman said that North Korea’s shelling of a South Korean island on Monday was “unforgiveable”. The chief Cabinet secretary, Mr Yoshito Sengoku, told a news conference in Tokyo that Japan “strongly condemns” the strike.

A French diplomatic source said the UN Security Council could hold an emergency meeting in the next day or two.

“It is necessary to immediately end all strikes,” the Russian foreign minister, Mr Sergei Lavrov, told reporters during a visit to the Belarussian capital Minsk. “There is a colossal danger which must be avoided. Tensions in the region are growing.”

China, the impoverished North’s only powerful ally, was careful to avoid taking sides, calling on both Koreas to “do more to contribute to peace”.

“It is imperative now to resume the six-party talks,” a spokesman for the Chinese foreign ministry told reporters.

China’s economic and diplomatic support have been important to shoring up its otherwise isolated neighbour, whose leader, Mr Kim Jong-il, has visited China twice this year to strengthen ties.

The Nato alliance, the European Union and Britain all condemned the North Korean attack, and Germany joined them in expressing concern and calling for restraint.

They said it could be aimed either at boosting its leverage in international talks — a tactic it has used in the past — or at reinforcing the domestic standing of the young heir apparent anointed by Kim Jong-il, his son, Mr Kim Jong-un.

“The shelling is likely succession-related in that the DPRK (North Korea) is seeking to build political capital for Mr Kim Jong-un by attempting to enhance the perception of Mr Jong-un's power base,” said Ms Brittany Damora, analyst at the risk advisory firm AKE.

“In the North’s view, Yeonpyeong is a great target in that it can strengthen the perception of its position without a real risk of counter-attack,” she said.

Mr Alastair Newton, political analyst at Nomura in London, said the South had made clear that it wanted to avoid an escalation, and that the sinking of the South Korean warship Cheonan in March, although denied by the North, had arguably been more serious because of the 46 lives lost.

“Bottom line: Together with possible preparations for a third nuclear test and the revelation at the weekend of the uranium enrichment facility, this looks like it could be North Korea playing hardball in anticipation of coming back to the negotiating table,” Mr Newton said.

One European diplomat said it was conceivable that the attack could be an attempt by a faction in North Korea's secretive leadership to sabotage attempts at rapprochement with the outside world.

The political risk consultancy Stratfor said the attack was at odds with other recent North Korean actions, noting that Pyongyang had sent a list of delegates to Seoul for Red Cross talks due to take place on Thursday.

“With the ongoing leadership transition in North Korea, there have been rumours of discontent within the military, and the current actions may reflect miscommunications or worse within the North's command-and-control structure, or disagreements within the North Korean leadership,” it said.