The protesters show no signs of leaving Government House
Protesters in Thailand are vowing more disruptive action, as their campaign to force the government of Prime Minister Samak Sundaravej to resign goes on.
Leaders from the People's Alliance for Democracy (PAD) say that their supporters will close more airports and bring out sympathetic unions on strike.
In a special parliamentary session on Sunday, Mr Samak rejected opposition calls for him to quit.
The situation has settled into an uneasy stalemate, say correspondents.
Thousands of PAD activists remain in control of Mr Samak's office in Bangkok as they enter the seventh day of protest.
They say his party is a front for former leader Thaksin Shinawatra, who was ousted by a military coup in 2006 and has fled the country to avoid facing trial over corruption charges.
Mr Samak has consistently rejected any concession to the protesters, but using force to evict them would be difficult and risky.
Last week pro-PAD protesters were able to close three airports, stranding thousands of tourists, and parts of the rail network.
Normal air services were said to have resumed on Sunday, but sections of the rail network remain suspended and now PAD supporters are promising more action.
Prime Minister Samak seemed to regain some confidence over the weekend, says the BBC's Jonathan Head in Bangkok.
On Saturday he was given an audience with King Bhumibol Adulyadej, although no details of their discussions have been made public.
On Sunday, he presided in characteristically pugnacious style over an emergency debate in parliament, where he still commands a sizeable majority, our correspondent adds.
The same day, in his weekly radio address Mr Samak repeated his threat to remove protesters occupying the government complex in Bangkok by force.
"I am not afraid, but I am concerned about chaos in the nation," he said, according to Reuters news agency.
"We cannot let the seizure of Government House continue indefinitely without taking action."
But our correspondent says there appear to be very few ways out of this crisis.
Sept 2006: Bloodless coup by military sees PM Thaksin Shinawatra removed from office
April 2007: New military-drafted constitution approved
Dec 2007: General election won by People Power Party (PPP), seen as reincarnation of Thaksin's now banned Thai Rak Thai party
Jan 2008: Samak Sundaravej chosen as PM
Feb 2008: Thaksin returns from exile
May 2008: PAD protests against Samak begin
July 2008: Thaksin goes on trial for corruption; his wife is found guilty of fraud. By mid-August the family has fled to the UK
August 2008: PAD protests escalate
The government retains strong rural support and would probably be re-elected if fresh polls were called - and the PAD does not support such elections.
The army, which is adopting a studiedly neutral position, will not assist in evicting the protesters from Government House - and the police are reluctant to act alone, our correspondent says.
Meanwhile, the revered King Bhumibol has also refused to intervene.
The outcome of this paralyzing dispute, therefore, probably hinges on which side first makes a mistake, or decides to back down and seek a compromise, our correspondent says.
So far neither side seems inclined to do so.
In a sign of the simmering tensions a small bomb exploded at a police traffic booth in the early hours of Monday.
No-one was injured.
The high point of confrontation so far has been Friday, when in addition to strike action, some 2,000 activists tried to storm police headquarters in the capital - only to be repelled by riot police.
The PAD was originally formed in the months before the 2006 coup, to demand Mr Thaksin's resignation. It re-emerged after Mr Samak - a former Thaksin ally - was elected last December.
It has a passionate following in various parts of the country, especially Bangkok, and some powerful backers among the elite.
But it has little support in most of rural Thailand, which voted strongly for Prime Minister Samak, and Mr Thaksin before him.