
Leaders of the anti-government movement on Friday rejected the prime minister's repeated offer for talks.
The Red Shirts said they will not enter into negotiations until the prime minister meets their conditions. They are demanding that he dissolve the country's parliament and call elections.
Many of the protesters are from poor, rural Thailand and support former Prime Minister Thaksin Shinawatra. He was ousted by a 2006 military coup because of alleged corruption.
Pro-democracy activists who oppose the army's role in government also have joined the rallies.
They say the Abhisit government came to power illegitimately with the military's support, after court rulings dismissed two Thaksin-allied governments.
Mr. Abhisit, who has the support of Thailand's royalists and urban elite, is refusing to call new elections.
Mr. Thaksin is living in self-imposed exile, avoiding a two-year prison sentence for graft in Thailand.
Police in Montenegro said Wednesday that Mr. Thaksin arrived in the Balkan state from Dubai on Saturday. Authorities said he has Montenegrin citizenship, and that they have no legal reason to take action against him.