International flights to and from Thailand's main airport were halted last night after rampaging anti-government protesters surged through police cordons and stormed the sprawling terminal.
The airports' authority said it had no choice but to close Bangkok's Suvarnabhumi airport as the yellow-shirted protesters carrying iron bars smashed doors and roamed the concourses.
The demonstrators from the People's Alliance for Democracy (PAD), which is dedicated to bringing down the prime minister, caused mayhem across Bangkok as they fired on government supporters and left 11 injured, one critically.
A PAD spokesman said last night that a bomb had been thrown at a group of its supporters outside the terminal, injuring three people.
Police lieutenant Suthep Wongsaeng said it was unclear what type of explosives were used in the early morning attack at the Don Muang Airport, nor who was responsible.
The closure of the international hub, which hosts 14.5 million tourists each year, is one of the most disruptive actions the group has staged in six months of protests that have unseated one prime minister and two ministers.
Last night leaders of the anti-democratic PAD vowed to keep the airport closed until the prime minister, Somchai Wongsawat, who is due to arrive home from an official trip today, resigns. His spokesman said he would not land at Suvarnabhumi.
The airport diverted incoming flights to Phuket, Chiang Mai and Singapore, after the departure area had to be closed because hordes of protesters pushed through lines of riot police, who were under orders not to use violence. Many demonstrators wore masks and goggles and attacked waiting taxi drivers with bats and golf clubs, before moving inside.
"There were a lot of people armed with sticks and baseball bats," said a Belgian tourist, Ben Creemers. "They looked ready for a fight."
The protesters, waving Thai flags and portraits of King Bhumibol Adulyadej, had blocked the motorway to the airport earlier. Many passengers had to drag heavy suitcases miles to the terminal in the hope of catching their flights, while others turned back or waited vainly by taxis.
The airport siege capped a dramatic second day of protest - billed as a "final showdown" - that saw violent clashes and several other mass protests designed to disrupt the government.
Earlier tens of thousands of PAD supporters picketed Bangkok's old Don Muang airport, which has become the temporary seat of power since the anti-government demonstrators occupied the prime minister's office in Bangkok last August. The protesters surrounded the airport's VIP building prevent a cabinet meeting yesterday, though no ministers appeared after the discussions were postponed.
A day earlier there were similar scenes outside parliament, which was besieged by tens of thousands of protesters even as that session was cancelled. There, too, police melted away as the authorities feared a repeat of clashes last month that left two demonstrators dead.
But yesterday some of the PAD mob made their way to Bangkok's army headquarters, where they believed the postponed cabinet meeting would be held.
Others, riding in a lorry, were ambushed on a Bangkok highway by government supporters who threw stones and poles. The PAD fought back with stones, bars and catapults. At least two men were seen firing revolvers at their rivals. Hospital officials said 11 pro-government supporters were injured, eight with gunshot wounds.
Earlier the PAD had urged government staff to strike to support their demand.
The PAD's desperate tactics are aimed at provoking the army to mount another coup - following that which deposed Thaksin Shinawatra in 2006 - as a way to unseat the government. But the PAD's extreme actions are alarming its broader base and polls show support for it is dwindling.