Tens of thousands of anti-government protesters have gathered in Thailand's capital Bangkok to press the government to step down and hold new elections.
About 40,000 soldiers and police are on the streets in case of trouble.
The Red Shirt demonstrators are mainly supporters of former Prime Minister Thaksin Shinawatra, who was ousted in a military coup in 2006.
Many of the protesters have come to the capital from Mr Thaksin's power base in the rural north of Thailand.
A BBC correspondent reports there are about 100,000 protesters.
They want to paralyse the capital and topple a government they say is a front for unelected elites.
Protest organisers say if this is not met their protests will spread to a number of other sites in the city.
On Saturday night the fugitive former prime minister Thaksin Shinawatra addressed his supporters by phone, he thanked them and told them to stay on the streets until the government falls.
The protest is set to be the biggest since the Red Shirts rioted in Bangkok in April, leaving two dead and scores injured.