Several thousand protesters pushed through a heavy police cordon around Thailand's seat of government Friday, vowing to peacefully besiege it until the prime minister resigns.

After initially scuffling with the demonstrators, police offered little resistance as crowds surged forward to a fence on two sides of the Government House compound.

The protesters, spearheaded by the People's Alliance for Democracy movement, claim Prime Minister Samak Sundaravej's government is a proxy for former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 military coup.

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Alliance leaders say they don't want to occupy the compound itself but plan to peacefully maintain a siege around it.

Chamlong Srimuang, an alliance leader, said the protesters would camp around the compound overnight and then stay on until Samak's coalition government resigned.

Samak, after meeting with the country's army commander and other senior security officials, declared the situation was under control and could be handled by police without help from the military, said Deputy Government Spokesman Nattawut Sai-gua.

There were no immediate plans to declare a state of national emergency or martial law, he said.

Police radio estimated that about 22,000 people were taking part in the protest. Alliance leaders gave far higher figures that could not be independently confirmed.

Reporters saw about a dozen protesters injured during the scuffles, but the police, although equipped with tear gas and water cannons, used minimal force. The Web site of the Bangkok Post newspaper said seven police officers were injured.

An almost festive atmosphere prevailed as protesters — many of them from Bangkok's middle class — waved, cheered and chatted with security officials. Others, dressed in the alliance's trademark yellow, shouted "Thaksin Out, Samak Out."

Their numbers swelled as people got out of work Friday evening and headed for the protest, whose organizers have been feeding thousands of people every night since the demonstrations began three weeks ago.

Police spokesman Maj. Gen. Surapol Tuanthong said about 5,000 police were deployed to block roads and prevent "the mob" from getting near Government House, a compound of ornate buildings from the 1920s set on 11 acres (4.5 hectares) of land.

Samak himself was not at Government House on Friday. He and all his ministers, as well as other government officials who normally work in the compound, were on leave or posted at other locations.

Samak, an avid cook, traveled to a nearby province to whip up food for students in a school nutrition program.

Government spokesman Wichianchote Sukchotrat said schools and government offices near Government House were ordered to close Friday for safety reasons and "to allow police to work smoothly."

The demonstrators — claiming their ranks would swell to 100,000 as reinforcements arrive from across the country — have been in Bangkok's streets for the past three weeks.

The alliance led mass demonstrations before the 2006 coup demanding Thaksin step down for alleged corruption and abuse of power. They now accuse Samak's government of interfering with corruption charges against the former prime minister and trying to change the constitution for its own self-interest.

Thailand's revered King Bhumibol Adulyadej met Samak on Thursday in an apparent attempt to defuse political tensions.

The king urged Samak to keep his pledges to do good for the nation, but did not publicly express criticism of his government. The protesters have repeatedly asserted they are defending royal interests.

One of the military's justifications for its 2006 takeover was a claim that Thaksin had not shown proper respect for the monarchy.

"I expect that you will do what you have promised and when you can do that, you will be satisfied," the king told Samak. "With that satisfaction, the country will survive. I ask you to do good in everything, both in government work and other work, so that our country can carry on and people will be pleased."

Samak's People's Power Party won general elections last December. His Cabinet is packed with Thaksin's allies, and critics say rehabilitating the former leader is among the government's top priorities.

This time around, the military has repeatedly said it will stay out of the political fray, with senior commanders trying to quash rumors of another coup.