PM Somchai Wongsawat's security agents and police shielded him and hustled him into a waiting car, which sped off in a motorcade.

The protest was staged by more than 100 employees of the state-owned telecom operator TOT during a visit by Mr Somchai to their headquarters outside the capital.

'It was not a serious protest,' the Premier later told reporters, describing the incident as a 'colourful protest' and adding that he forgave the protesters.

It marked the first time in Thailand's months of political crisis that state employees have come into direct confrontation with the Prime Minister.

It was not, however, the first time that Mr Somchai has had to make a quick getaway. On Oct 7, he escaped a violent protest outside Parliament by climbing over a back fence to safety. Riot police outside the building fired tear gas to disperse rowdy protesters, leaving hundreds injured and two dead.

Yesterday's rally started outside the TOT headquarters, on the grounds of the Ministry of Information and Communications Technology.

PM Somchai's motorcade made a detour into an underground parking lot to avoid the crowd shouting 'Somchai, murderer!', in reference to the two fatalities at the Oct 7 protest.

Protesters swarmed around him in the parking lot, waving noisy plastic clappers shaped like giant hands.

After holding a meeting inside the building, the Premier made his exit through the main entrance, where more protesters had gathered. Some hurled clappers, plastic water bottles and shoes at his entourage. Throwing shoes is particularly insulting in Thai culture, which considers the feet the dirtiest part of the body.

Mr Somchai, who took office last month, has come under growing pressure to step down to ease Thailand's deepening political crisis.

Yesterday, anti-government demonstrators said they were clearing one protest site, but rebuffed pleas to dismantle their main camp at the Prime Minister's offices. Leaders of the People's Alliance for Democracy said they had begun clearing stages from the secondary site near the United Nations headquarters, to let royal motorcades through.

ASSOCIATED PRESS, AGENCE FRANCE-PRESSE