Government opponents and supporters of Thailand's former prime minister, Thaksin Shinawatra, launched a rally by blockading the government's main administrative building and calling for Thai Prime Minister Abhisit Vejjajiva to resign.  The rallies appear to be part of a new strategy by Thaksin supporters to weaken the Abhisit government that came to power in December.

Rousing speeches and stirring march music were the backdrop as nearly 20,000 government opponents and supporters of former Prime Minister Thaksin Shinawatra staged a rally and blockade of the government's main administrative building in Bangkok.

About 3,000 police were deployed around the building with a further 2,000 army troops on standby.

The rally was organized by the United Front of Democracy Against Dictatorship, whose supporters dress in red. 

Khun Wachara said he was protesting the government of Prime Minister Abhisit Vejjajiva, which came to power in December.  Mr. Abhisit formed a coalition government after court decisions banned several ministers in a pro-Thaksin government.

"We would like to promote democracy process in Thailand.  We would like to protest injustice and unfair government in the parliament," he said.  "We want to show general people that most of Thai people do not like the illegal government, do not like the illegal movement that destroy democracy, destroy the rule of law."

Ousted in a coup in 2006, Thaksin-backed parties won general elections in December 2007.  He fled Thailand last year before a corruption court verdict that sentenced him to two years jail.

Efforts by pro-Thaksin governments to rehabilitate the former prime minister and supporters from political bans and court cases met with resistance and protests in Bangkok.

The People's Alliance for Democracy launched protests in May last year against the pro-Thaksin government.  These included occupying the government house compound for more than three months as well as the two main airports in Bangkok for more than a week. 

Thailand's urban middle class accuses Thaksin and his government of corruption and abuse of power.  But he remains popular among rural workers and urban poor due to his populist economic policies.

Protester Chirowat Upapong says he hopes Thaksin will return soon.

"I hope he will come back, come back again soon," said Chirowat.  "Most of the people respect him so much and he has the power can make clear every problem in my country."

Rally protesters are pressing for the government's resignation as well as prosecution of leaders from last year's rallies.  The current government has allowed Thai police to issue warrants against 21 key leaders in last year's rallies.

Thailand is to host a South East Asian leaders summit later this week.  The ASEAN meeting had been postponed last year due to the protests.