A grenade attack killed an anti-government protester at a besieged Bangkok airport on Tuesday, as further unrest forced a key hearing on the possible dissolution of the ruling party to move.

The incidents raised tensions in an increasingly bloody political stand-off that began a week ago, stranding about 350 000 frustrated travellers, including South Africans, and causing massive damage to Thailand's economy.

The attack at Don Mueang airport was the latest in a series targeting the royalist People's Alliance for Democracy (Pad), which has occupied the domestic terminal and Bangkok's larger international airport.

"A 29-year-old man was killed and 22 others wounded in a bomb attack early on Tuesday (at Don Mueang)," an emergency services spokesperson told AFP. She said the man died from shrapnel wounds to the stomach.

It came just hours after the royalist Pad ended a three-month sit-in at the prime minister's offices in Bangkok following a series of similar grenade attacks, and redeployed its forces to both airports.

Divisions in Thai society

In a sign of the divisions in Thai society, hundreds of rival pro-government supporters later sealed off central Bangkok's Constitutional Court, where judges were set to hear closing arguments in a vote fraud case.

The judges moved to another court on the outskirts of town to consider whether to disband three parties in the ruling coalition because some of their executives were convicted of vote fraud after elections in December 2007.

No date for the verdict has been set, but if it goes against the ruling People Power Party (PPP) it would also see Prime Minister Somchai Wongsawat banned from politics for five years.

Expecting the decision to go against the party, government supporters in bright red shirts massed around the court building and set up makeshift stages on trucks, witnesses said.

"The final hearing will now begin at the Administrative Court building," a court spokesperson told AFP.

Protesters wore headbands and scarves reading "Against Dictatorship" and "Love Thaksin," a reference to premier Thaksin Shinawatra, who was ousted in a 2006 coup. They later moved to the Administrative Court.

Hundreds of police armed with batons stood guard at the Constitutional Court and soldiers were also deployed around the building, amid fears of clashes between the Pad and pro-government groups as tensions escalate.

Dressed in red and yellow

The Pad launched its campaign in late May, accusing the government elected in December of acting as a proxy for Thaksin — Somchai's brother-in-law — and of being hostile to the monarchy.

The Pad, who dress in yellow which they say symbolises their devotion to Thailand's much-revered king, are backed by the Bangkok business elite and middle classes, along with elements in the military and the palace.

Thaksin, whose supporters dress in red, is hugely popular with Thailand's rural and urban poor, especially in the north, his native area.

Somchai has been marooned in the northern pro-government stronghold of Chiang Mai since Wednesday, but is due to attend a military ceremony later Tuesday ahead of the king's 5 December birthday.

Thais may also be waiting for King Bhumibol Adulyadej, the world's longest reigning monarch, to point to a way out of the crisis in a birthday-eve speech on Thursday.

The blockade continued to take a toll on tourists who are flooding to a naval base southeast of Bangkok and to the southern tourist town of Phuket to try to escape the so-called "Land of Smiles".

Two Canadians were killed and a Briton seriously injured in a car crash on Monday as they headed to Phuket from Bangkok to catch a Cathay Pacific flight, police said.

A Hong Kong national was killed in a similar traffic accident on Sunday as he also tried to get to Phuket.

AFP