Philippine foreign ministry sources said fear of an imminent terror strike on Cebu, a resort island popular with Western tourists that was to host the summit, was a major factor in Friday's decision.

 The postponement until January was announced one day after several nations, including the United States, issued a warning for Cebu due to threats of a terrorist attack. Australia said attack plans were in the "final stages".

 Sixteen presidents or prime ministers had been scheduled to arrive in Cebu before organisers called off the Association of Southeast Asian Nations (Asean) summit and the wider East Asia summit, scheduled for December 10-14, at the last minute.

 Late Friday a planned meeting of foreign ministers from the Association of Southeast Asian nations and China, Japan and South Korea was also scrapped.

 Philippine officials cited worries about a looming Pacific storm that had intensified into a typhoon by Saturday morning, but acknowledged that weather forecasters had not recommended cancelling the summit.

 "The threat of a terrorist attack was one part (of the reason)," one source at the foreign ministry told AFP.

 Mike Clancy, one of the organisers of an Asean business and investment forum on the sidelines of the political events, said political leaders and ministers were not believed to have been in danger.

 "The real fear was an incident on the fringes of the summit and that fear was very real," he told AFP without elaborating.

 It was not clear what sparked the multi-national terror warnings.

 Two Muslim militant groups, Abu Sayyaf and the Indonesia-based Jemaah Islamiyah, have launched deadly attacks in the Philippines in recent years.

 Just before the postponement was announced, an official of the justice department's National Bureau of Investigation told reporters that police had been put on alert for a possible threat to Cebu's water supply.

 Meanwhile the government weather bureau said on Saturday that Tropical Storm Utor had intensified into a typhoon.

 As of 8:00 am (0000 GMT) it was about 90 kilometres (60 miles) east of the central island of Samar, moving northwest at 22 kilometres per hour with maximum winds of 120 kilometres per hour.

 It is expected to hit Samar, roughly 200 kilometres away from Cebu, later Saturday, the weather bureau said.

 But only a lower-level storm alert was in force in Cebu island.

 "We had prepared for a possible typhoon. It was not a problem as far as we could see," said Nagiel Banacia, a spokesman for Cebu City mayor Tomas Osmena.

 "This has been terrible for Cebu. Everyone is down."

 House Minority Leader Francis Escudero said separately he did not believe typhoon-related fears caused the postponement.

 Philippine Foreign Minister Alberto Romulo said it was hoped a date for the rescheduled summit could be set within a week.

 He said ministers "appreciated the concern the Philippine government has shown for the safety and welfare of all the participants."

 In signs of the hasty exodus, only four Asean foreign ministers attended a breakfast meeting Saturday.

 Sebastian Loh, of the Singapore business federation, supported Manila's postponement. "I don't think it will impact that much. It's just a couple of weeks."

 But another business leader said the gathering would be remembered as the summit that failed.

 "For Cebu itself this has been a disaster," he told AFP on condition of anonymity. "A lot of money went into this to promote Cebu as a safe tourist destination. Many delegates will not come back."

Agence France Presse