SINGAPORE—Southeast Asian countries Wednesday said they regretted that Thailand's political turmoil drove it to postpone a regional summit, with Singapore urging prompt cooperation on the world financial crisis.

The summit of the ASEAN bloc was to take place in Thailand in mid-December but was postponed to March, Thai government spokesman Nattawut Saikaur said Tuesday, at the peak of an anti-government protest that shut down Bangkok's airports.

Singapore urged that the summit of the Association of Southeast Asian Countries be held sooner, however.

"While Singapore understands why the summit has to be postponed, it should not be delayed more than absolutely necessary," Singapore's foreign affairs ministry said in a statement late Tuesday.

"With the global financial crisis affecting all countries in ASEAN, the summit should be rescheduled to the earliest possible date, preferably in January, rather than later in March."

The planned venue for the summit had already been shifted out of Bangkok to the northern Thai city of Chiang Mai because of the political turmoil that has gripped the country for months.

Thailand's constitutional court on Tuesday dissolved the ruling party and barred Prime Minister Somchai Wongsawat from politics for five years.

The airport siege cost Thailand economically and dented its international image both as a tourist haven and a beacon of stability in the region.

ASEAN leaders were to be joined at the summit by leaders of governments from East Asia as well as the heads of international organizations, including the United Nations, World Bank, International Monetary Fund and World Trade organization.

Laos, Cambodia and Vietnam had called for a postponement.

ASEAN groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. Thailand holds the rotating chairmanship.

Malaysia raised doubts over whether Thailand would be able to host the summit at all.

"We'll have to wait (to see) whether Thailand of the future will be able to furnish for us in ASEAN the commitment for the summit," Foreign Minister Rais Yatim told a news conference, while expressing "sadness" about the turmoil.

"Malaysia only hopes that the next government or the next authority in Thailand would be able to foster and germinate the essentials of ASEAN," Rais added.

Singapore's foreign ministry said ASEAN should consider holding the summit instead at the bloc's Jakarta-based secretariat.

Cambodian Prime Minister Hun Sen expressed "regret" for the postponement, government spokesman Khieu Kanharith told reporters in Phnom Penh, adding that Cambodia hopes Thailand can "solve the problem very soon".

The Philippines hailed Thailand's decision, however.

"A postponement would be favorable given the present circumstances," Philippine President Gloria Macapagal-Arroyo's spokeswoman Lorelei Fajardo told reporters.

"It will give Thailand more time to resolve its political crisis and give the members more time to prepare," she said, adding the "safety of participants must also be ensured."