Riot police took up positions early on Wednesday around Thailand's main government compound, as authorities tried to negotiate an end to protests aimed at forcing Prime Minister Samak Sundaravej to resign.
Scuffles between protesters camped out overnight and police reporting for duty led to a few minor injuries, deputy national police spokesman Major General Surapol Tuanthong told AFP, but insisted there would be no violence.
"They are not going to disperse the crowd -- we are trying to negotiate," Surapol said, adding that warrants for the arrest of key protest leaders were expected to be issued later on Wednesday.
On Tuesday, up to 35,000 demonstrators seized a state-run television station, invaded the grounds of Government House and besieged at least three ministries, stepping up their campaign to bring down Samak's administration.
The People's Alliance for Democracy (PAD), which has been protesting since May, claims Samak is running the country on behalf of former premier Thaksin Shinawatra, who was ousted in a 2006 coup and is barred from holding office.
Surapol said about 8,000 protesters remained within the government compound on Wednesday, while an AFP correspondent at the scene said hundreds of police, some armed with batons and shields, had entered the enclosure.
The security forces appeared relaxed, sitting and watching the ongoing rally on the manicured lawns of Government House, which included speeches and group singing.
Police refused to reveal how many police were stationed in and around Government House, saying only it was enough to maintain law and order.
Army-run Thai television Channel Seven earlier reported that Interior Minister Kowit Wattana had entered the compound to negotiate with leaders.
"So far there is no positive response from them," deputy government spokesman Nuttawut Saikuae told state television.
One protest leader, Chamlong Srimuang, told the crowd: "Police will seek the warrants (for our arrest) on Wednesday. Don't panic -- if we have been arrested, others will carry on."
Another leader, Somsak Kosaisuk, vowed that demonstrators would not surrender.
"If you want to arrest us, come here and arrest us here -- it is the government who must go," he told the protesters, most of whom were wearing yellow shirts out of allegiance to revered King Bhumibol Adulyadej.
Thailand's two English-language newspapers, known for their criticism of the government and anti-Thaksin stance, sharply criticised the PAD's actions.
"Dark days descending once again," wrote The Nation, saying: "The PAD's highly provocative action yesterday was completely uncalled for."
The Bangkok Post described Samak's calm reaction to the crisis as "commendable", while calling the PAD's actions "unjustified, unnecessary, provocative and illegal."
Media rights watchdogs, meanwhile, criticised the raid of the state-run television station on Tuesday, saying the temporary closure and violence at the offices had threatened freedom of the press.
Samak, who was working Wednesday from army headquarters, said on Tuesday his approach would be "soft and gentle," and said police would simply surround the seat of government until everyone had left.
"They (the PAD) want bloodshed in the country, they want the military to come out and stage a coup again," Samak told a press conference.
"I will not resign, I will stay to protect this country," he added.
PAD protests in early 2006 helped lead to the putsch that unseated Thaksin, and the entry to government of his ally Samak infuriated the old power elites in the military and palace, who resented Thaksin's hold on rural voters.