Anti-government protesters break into Thai Finance Ministry

Anti-government protester touches the hand of a policemen across barbed wire after giving him flowers at a barricade near a government building in Bangkok

BANGKOK – About 1,000 anti-government demonstrators forced their way into Thailand’s Finance Ministry on Monday and protest leaders called for the occupation of government buildings in an escalating bid to topple Prime Minister Yingluck Shinawatra.

The mass protests against Yingluck and her brother, ousted premier Thaksin Shinawatra, are the biggest since 2010 when the kingdom was rocked by its worst political bloodshed in decades with more than 90 civilians killed.

The turmoil has raised fears of a fresh bout of street violence in a country that has been convulsed by several episodes of political unrest since royalist generals overthrew Thaksin in a coup in 2006.

Police said around 30,000 protesters opposed to Yingluck's elected government marched on more than a dozen state agencies across the capital on Monday including military and police bases, as well as several television stations.

Hundreds of demonstrators, spurred on by protest leader Suthep Thaugsuban, occupied buildings in the compound of the finance ministry, waving flags and dancing, according to AFP correspondents at the scene.

"Tomorrow we will seize all ministries to show to the Thaksin system that they have no legitimacy to run the country," Suthep said, addressing the crowd through a loud speaker.

Chanting "Thaksin get out, army come in", some of the demonstrators had earlier called for the intervention of the military in a country that has seen 18 actual or attempted coups since it became a constitutional monarchy in 1932.

The move comes after a boisterous rally on Sunday brought up to 180,000 anti-government demonstrators on to the streets of Bangkok, according to a revised estimate Monday from National Security Council chief Paradorn Pattanatabut.

Around 50,000 pro-government "Red Shirts" met overnight in a suburban football stadium in Bangkok in support of Yingluck and Thaksin, who remains a hugely divisive figure in Thailand.

The rallies are the biggest challenge yet for Yingluck, who swept to power in elections in 2011 on a wave of support from the "Red Shirts", whose protests in 2010 were crushed by the previous government.

Yingluck on Monday told reporters she would neither resign nor dissolve parliament despite the mounting pressure.

But experts said she is running out of room to manoeuvre.

"Yingluck's options are very limited. Something has to give this week. It will be very difficult for Yingluck to stay in office, let alone get anything done," said Thitinan Pongsudhirak, director of the Institute of Security and International Studies at Bangkok's Chulalongkorn University.

The Thai capital has faced weeks of opposition-backed rallies sparked by an amnesty bill that could have allowed the return of Thaksin from self-imposed exile.

The amnesty bill - which was rejected by the upper house of parliament - also angered Thaksin's supporters because it would have pardoned those responsible for the 2010 military crackdown on their rallies.

Former premier Abhisit Vejjajiva - now the opposition leader - and his deputy Suthep face murder charges for overseeing the military operation, which involved soldiers firing live rounds and backed by armoured vehicles.

In another blow to the government, the Constitutional Court last week blocked the ruling party's plans for a fully elected Senate.

The opposition Democrat Party is seeking to raise the pressure on Yingluck with a no-confidence debate on Tuesday - although her party dominates the lower house and should comfortably defeat a move against her.

Thaksin, a billionaire telecoms tycoon-turned-politician, draws strong support from many of the country's rural and urban working class, but is loathed by the elite and the middle classes, who accuse him of being corrupt and a threat to the monarchy.

"Yingluck, Thaksin, their party and their corrupt system must go this week," demonstrator Thanabhum Prompraphan, 50, told AFP.

"This is real people power. We will stay peaceful... whistles are our weapons," he said.

A series of protests by the royalist "Yellow Shirts" helped to trigger the coup that toppled Thaksin, who now lives in self-imposed exile in Dubai to avoid a prison term for corruption that he contends was politically motivated.

King Bhumibol Adulyadej, 85, is widely revered in Thailand but has been in ill-health for several years and the palace has been silent over the organisation of his eventual succession.