A state of emergency has been declared in Thailand at two airports besieged by anti-government protesters in Bangkok.
Rumours of a coup are swirling around the Thai capital.
In a televised address, Prime Minister Somchai Wongsawat said some police and military units will try to end the blockades at Suvarnabhumi and Don Muang airports.
Suvarnabhumi is one of Asia's busiest airports and gateway for nearly 15 million visitors to Thailand each year.
The People's Alliance for Democracy refuses to end the protests, which have forced flight cancellations and stranded thousands of travellers since Tuesday.
The PAD says the protestors will not leave and it will use people as human shields if the police try to make them.
The government intends to shuttle thousands of tourists by bus to U-Tapao naval airbase as an alternative for airlines.
The Canadian Broadcasting Corporation reports rumours of a military coup are swirling around Bangkok and imminent developments are expected.
Thailand has been in a state of political stalemate since former Prime Minister Thaksin Shinawatra was ousted in a military coup in 2006.
Fresh elections at the end of 2007 failed to resolve the crisis, when a party made up of former allies of Mr Thaksin returned to power.
The PAD - a loose alliance of royalists, businessmen and the urban middle class - claim that the government is corrupt and hostile to the monarchy.
They also accuse it of being a proxy for Mr Thaksin, who remains very popular among Thailand's rural poor.