Anti-government protesters attack a police officer outside a government base in Bangkok.
• Protests cancel Thai parliament session November 24, 2008Story Highlights
NEW: Parliament postpones Monday session after protesters surround building
Demonstrators want to prevent Parliament from considering revising constitution
Nearly 100,000 protesters were involved on October 7 rally, which turned deadly
BANGKOK, Thailand (CNN) -- Thousands of anti-government protesters marched on Thailand's Parliament Monday morning, causing lawmakers to postpone their session fearing violence, said House speaker Chai Chidchob.
Thousands of protesters march to Parliament in Bangkok on Monday.
Protesters, led by the People's Alliance for Democracy, also surrounded Bangkok's police headquarters and the finance ministry building.
The demonstrators brought their own guards who were armed with clubs and long wooden poles in anticipation of clashes with police and pro-government supporters.
The anti-government alliance accuses the current administration -- led by the People Power Party (PPP) -- of being a proxy government for one-time Thai Prime Minister Thaksin Shinawatra.
The protesters want the resignation of the current prime minister, Somchai Wongsawat, who is Thaksin's brother-in-law.
Thaksin was ousted in a bloodless coup in 2006, but he returned to Thailand after the PPP swept into power in December 2007.
Then, in August, he fled again just as he was to appear in a corruption case against him.
The protesters want Thaksin extradited and tried on those charges.
It also accuses the PPP government of wanting to amend the constitution so Thaksin does not have to face charges.
The protesters have held almost-daily demonstrations since May. They seized the Government House in late August, fortifying it with sandbags, tires and shells of burned-out buses.
In September, the protesters accomplished one of their goals when Thailand's Constitutional Court stripped Prime Minister Samak Sundaravej of his position, ruling that he had violated the constitution by appearing as a paid guest on a television cooking show.
The PAD had been demanding Samak's ouster.
But the PPP responded by picking Thaksin's brother-in-law as Samak's replacement -- further inflaming the protesters who have continued their campaign.
The last time protesters marched on Parliament, police efforts to disperse them resulted in running street battles, The Associated Press reported. Two people were killed and hundreds injured in the October 7 violence.