Hundreds of supporters of deposed Thai Prime Minister Thaksin Shinawatra began in Bangkok for a series of anti-government protests over the weekend.

The rallies are seen as the biggest threat yet to Prime Minister Abhisit Vejjajiva.

[Jatuporn Prompan, Protest Leader]:
"We are gathering in groups nationwide at noon today to drum up our campaign in small groups. The real big gathering will be on the 14th."

Protesters listened to speeches and music over loudspeakers while waiting for leaders to arrive in trucks that would be turned into makeshift stages.

More plan to arrive over the weekend with hundreds of thousands expected on Sunday.

Many businesses and schools have closed in Bangkok while some companies allowed staff to work from home.

Security forces guarded state buildings after government warnings of arson and bombings.

Protesters say authorities are trying to fan public fears to justify a potential crackdown.

The government insists the threat of violence is real and that it wants to ensure that there are enough forces in place to prevent any chaos.

[Suthep Thaugsuban, Deputy Prime Minister]:
"Our 50,000 security personnel are not armed, I've made it clear that the only people who will be armed are police officers on regular duty to patrol and keep peace in residential areas. The soldiers and other forces who handle the protest will not be armed."

Government House, which includes Prime Minster Abhisit's office, has been cordoned off.

Authorities have closed several other roads near where protesters said they may march.