Thailand's PM Surayud Chulanont casts his vote during a referendum on a new constitution at a polling station in Bangkok, 19 Aug 2007

Shortly after polling stations closed at 4 p.m. local, Thai television said exit polls showed the constitution had been approved.

TV announcers and online news reports said the Rajabhat Suan Dusit University poll showed about 68 percent of voters accepted the draft. Other polls carried similar results.

Military-installed interim Prime Minister Surayud Chulanont quickly claimed victory. Appearing on national television early Sunday evening, he thanked Thai voters for their support, said the constitution would be submitted for the King's approval this month and elections for a new government would be set for December.

Pakern Sardaruwong, a 29-year-old law student, casting his approving vote central Bangkok, says his vote is a vote for democracy.

"I come here for the democracy of Thailand; the people of Thailand need it - the democracy," said Pakern Sardaruwong.

But critics say the charter is flawed because it was drafted by a military-appointed panel and the referendum was not a fair test of support. If voters had rejected the constitution, the government could have imposed any of Thailand's previous 17 constitutions and amended them freely.

A retired naval officer, who gave his name Khun Nat, says he preferred the 1997 constitution that was nullified with last year's coup.

"I think the old constitution is better. I voted no - not approve. The constitution belongs to the 'tahan' [military] not democracy. So I vote no. However, I think we will have an election within this year - I am sure," he said.

Defenders of the draft constitution say it introduces more checks and balances on executive power and limits the type of political manipulation they claim was used by ousted prime minister, Thaksin Shinawatra, to dominate parliament.

The 186-page charter reduces the number or parliamentary seats, calls for half the Senate to be appointed instead of directly elected, shifts some power from the executive to the judiciary and limits the prime minister's time in office.

Government spokesman, Yongyuth Mayalarp, says the referendum sends an important message to the international community.

"This is proof to the international audience that the present government, under General Surayud Chulanont, is keeping to the timetable as promised to the general public of returning to democracy again - that's when we've been doing all the way through," said Yongyuth Mayalarp.

Some 45 million voters were eligible to cast ballots at some 87,000 polling booths across the country. Voting was free of any disruption amid tight security.