BANGKOK -- (UPDATE) Thai protesters Monday began leaving the prime minister's offices after a three-month sit-in, moving instead to reinforce a paralyzing anti-government blockade of Bangkok's two airports.
Leaders of an alliance trying to force premier Somchai Wongsawat to resign said they were worried by recent grenade attacks which have killed two protesters and wounded dozens more at Government House in the capital.
In another apparent climb-down, the People's Alliance for Democracy (PAD) allowed 37 empty aircraft to fly out of Bangkok's Suvarnabhumi international airport in the past two days.
"It's too risky to stay at Government House because of repeated attacks against us," PAD spokeswoman Anchalee Paireerak said. "All of us have started to move now. We expect to complete the movement this evening."
An Agence France-Presse (AFP) reporter saw dozens of supporters carrying plastic bags and sleeping mats leaving the compound, which protesters had heavily fortified with razor wire and tires.
The PAD seized the cabinet offices in late August, as part of a campaign they launched in May to topple an elected government they accuse of running the country on behalf of former premier Thaksin Shinawatra, ousted in a 2006 coup.
They took that campaign to unexpected heights last week, storming the main international airport on Tuesday and then occupying the older Don Mueang domestic airport the next day.
The abandonment of the premier's offices will likely ease the risk of clashes with a rival pro-government group who camped out in Bangkok for a second day a few kilometers from Government House.
About 15,000 red-shirted pro-government activists had converged on city hall in downtown Bangkok on Sunday night, and around 1,500 of them remained there on Monday morning, police said.
"We will rally again this afternoon at the same place," Chinawat Haboonpard, a leader of the pro-government group, told AFP.
Chinawat said the group had not yet decided whether to launch a blockade of the Constitutional Court, which is due Tuesday to wrap up a case that could see the ruling party disbanded for vote fraud and Somchai banned from politics.
Over the last three months the PAD turned the compound around the Venetian-style Government House into a sprawling tented city, complete with portable toilets, food stalls, stages and massive television screens.
But unknown groups have launched grenade attacks at the site. On Sunday, 49 protesters were injured in a blast.
Government spokesman Nattawut Saikuar said Prime Minister Somchai had been notified about the end of the siege.
"I expected the protesters to gradually abandon the site because it's clear they will not achieve victory. After they occupied the airports, the rest of society is against them," he told AFP.
But with the airports still blocked, a number of nations sent emergency flights to evacuate the estimated 100,000 travelers stuck in Thailand for the last week.
Australian airline Qantas and Air France-KLM sent extra planes to southern Phuket to bring home hundreds of travelers.
France and Spain have also sent planes to the Vietnam War-era U-Tapao naval base about 200 kilometers southeast of Bangkok, which has been the main exodus point since last week.
Protesters say they will not disperse from the airports until Somchai -- who is Thaksin's brother-in-law and is currently in northern Chiang Mai city -- steps down.
Thaksin and his allies draw huge electoral support from Thailand's largely rural northern poor, while the PAD is backed by the Bangkok business elite and middle classes, along with elements in the military and the palace.
Thais may also be waiting for any sign on a way out of the crisis from the deeply-respected King Bhumibol Adulyadej, who is due to give a birthday-eve speech on Thursday.
