The political crisis, which entered its seventh day with no sign of either side backing down, peaked on Friday when police fired teargas and rubber bullets to repel 2,000 protesters trying to storm Bangkok police headquarters.

Members of the People's Alliance for Democracy (PAD) shut down three regional airports on Saturday and Sunday, paralysing the country’s transport system. Today all three have re-opened.

Police blamed Monday morning’s bomb attack on demonstrators who are trying to sow “chaos in the nation” and depict government and police as incapable of maintaining order and contain demonstrations.

The bomb detonated shortly after the end of a joint session of parliament called by Prime Minister Samak Sundaravej to seek a way out of the political crisis and avoid a violent escalation.

Samak, who has been accused of being a puppet in the hands of former Prime Minister Thaksin Shinawatra now in exile in London, rejected calls to quit or hold a snap election.

In his weekly radio address on Sunday he warned that his patience was wearing out.

“I am not afraid,” he said, “but I am concerned about chaos in the nation. We cannot let the seizure of Government House continue indefinitely without taking action.”

Despite demands for the premier’s resignation made by PAD leaders, who are close to the crown and the country’s conservative camp, the current government remains popular.

The PAD has a following in various parts of the country, especially Bangkok, but it has little support in most of rural Thailand, which remains loyal to current Prime Minister Samak.