The Philippines has postponed twin summits of East Asian and Southeast Asian leaders due to open this weekend amid fears of an incoming typhoon, a Japanese official said.
"Both of the summits will be postponed," the foreign ministry official told AFP in Tokyo, under cover of anonymity.
"But it is still not known until when they will be postponed."
The official said the Philippine government was expected to make a formal announcement soon about the summits.
The 10-nation Association of Southeast Asian Nations annual meeting was to have begun Sunday on the holiday resort island of Cebu and to be followed by a wider summit bringing in countries such as Australia and China.
The surprise move came a day after Philippine officials furiously denied a string of warnings issued by other governments about the threat of possible terror attacks.
Australia, Britain, Japan, New Zealand and the United States had all issued warnings for travel to Cebu, with the Australians cautioning that plans for an attack were "in the final stages."
The Japanese foreign ministry official said, however, that Japanese Prime Minister Shinzo Abe would leave later Friday for Manila for a bilateral visit and return on Sunday.
Kyodo News, quoting unnamed sources, said the summits may be rescheduled to January.
A tropical storm, codenamed "Utor", was charted at 0200 GMT at around 550 kilometers (341 miles) east of the central island of Samar, moving west at 24 kilometers per hour, the government weather station said.
It could strike the eastern Bicol region already devastated by last week's typhoon Durian, which triggered volcanic mudflows that left more than 1,300 people dead or missing.