BANGKOK - Thousands of protesters surrounded the prime minister's office Tuesday demanding Thailand's Parliament be dissolved and new elections held.

The rally by demonstrators allied with exiled former Prime Minister Thaksin Shinawatra came three days before Thailand is to host the annual summit of the 10-member Association of Southeast Asian Nations. About 7,000 people attended, police said.

One of the protest leaders, Jakrapob Penkair, said the demonstration was being staged this week to show Thailand's Southeast Asian neighbors that the government of Prime Minister Abhisit Vejjajiva had no right to rule.

Abhisit became prime minister in December after a court ruling that ousted a government of Thaksin's allies -- but only after the former leader's opponents spent much of last year demonstrating in the capital, occupying the prime minister's offices for three months and Bangkok's two airports for a week.

Abhisit's Democrat Party, which came in second in a December 2007 general election, cobbled together a ruling coalition from defecting supporters of the previous administration.

"This government is full of robbers. We did not vote for them. The majority of this country did not vote for them but somehow they are in power because the elite want them to be," said Jatuporn Phromphan, another protest leader, on top of a pickup truck amid loud cheers.

Abhisit's government held its weekly Cabinet meeting in Hua Hin, 150 kilometres southwest of Bangkok, instead of its usual venue at Government House, at which some 3,000 police in riot gear were deployed. Two-thousand army troops were on standby in the area, said police Lt. Gen. Worapong Chiewpreecha.

"We will not use violence," Abhisit told reporters. "I am not concerned. I am ready to walk into (the Government House) as long as there are no weapons."

Jakrapob said the demonstrators would camp out there for at least two days to press their demands but would not break in as their political rivals had done.

The demonstrators also demanded the resignation of Foreign Minister Kasit Piromya, who was a vocal supporter of the anti-Thaksin demonstrators who besieged the airports last year.

The Tuesday protest was organized by the Democratic Alliance against Dictatorship -- commonly known as the "red shirts" because of their attire, which contrasts with the yellow shirts worn by their rivals, the self-styled People's Alliance for Democracy. The DAAD is an eclectic mix of Thaksin loyalists, rural farmers and laborers, all of whom benefited from Thaksin's policies that reached out to the poor.

Thaksin, a former telecommunications tycoon, remains popular among the rural majority for introducing social welfare plans, including virtually free medical care. He now lives in self-imposed exile after being forced from office in a 2006 military coup for alleged corruption and abuse of power.