Thailand's army said today it would begin limiting supplies of water, food and electricity to protesters camped in central Bangkok in a bid to clear the streets by midnight.
Colonel Sansern Kaewkamnerd said security forces "will not use force at this stage", raising concerns of more violence in Thailand's two-month political stand-off if the protesters refused to disperse.
The new measures were announced a day after prime minister Abhisit Vejjajiva warned protesters to leave by today.
Meanwhile the chances of a negotiated settlement to the protests appeared to be unravelling.
Government spokesman Panitan Wattanayagorn said earlier that the prime minister had withdrawn his compromise offer to hold early elections on November 14 as part of a reconciliation plan.
He said Abhisit Vejjajiva had now issued instructions for quickly dealing with the so-called Red Shirt demonstrators who are occupying a central commercial district in Bangkok to press their demands.
Asked whether this implied a new crackdown by security forces, Mr Panitan said last night: "The prime minister has already handed out some guidelines. Tomorrow they will be implemented."
The protests have paralysed a central portion of Bangkok that is home to several glitzy malls and luxury hotels, devastating the economy, particularly the vital tourism sector.
Last week Mr Abhisit told the Red Shirts - mostly poor rural Thais who view his government as illegitimate - that he was willing to hold new polls in November, more than a year before the end of his government's term.
That was presented as part of a reconciliation package if the demonstrators would end their protest and seen as the way out of the crisis.
The Red Shirts, who have been pressing for quick elections, said they agreed in principle, but gradually added a list of conditions of their own including that Mr Abhisit and his top deputy surrender to police over an April 10 attempt by security forces to disperse protesters that left 25 people dead.
"If petty issues keep being brought up, it's not going to end because the government isn't going to compromise," Mr Abhisit told reporters, adding that people's patience with the demonstrators had frayed due to the hardships and losses they had suffered.
"What is essential right now is to return normalcy to society," he said.
Mr Panitan said the initial conditional election offer had now been withdrawn.
"Their refusal to stop the protest meant that the conditions that were set are being cancelled, including the election date," he said.
Mr Abhisit took the new stand after demonstrators insisted earlier that they would continue their protest despite deputy prime minister Suthep Thaugsuban reporting to Thailand's equivalent to the FBI and the government saying both leaders were willing to submit themselves to judicial processes.
But the protesters - formally known as the United Front for Democracy Against Dictatorship - said the gesture was not enough. They want the leaders - particularly Mr Suthep, who heads the security agency whose mandate is to suppress their protest - charged with manslaughter or similar offences.
No criminal charges have been filed against either of the men.
Several violent incidents related to the Red Shirt protest have killed 29 people and wounded more than 1,400, according to a health ministry announcement on Monday.
More than two dozen Red Shirt leaders already face a variety of charges, ranging from breaking the terms of a state of emergency to weapons offences and assaults on government officials.
The most serious charges, related to disruption of public transport services, infrastructure and telecommunications, are covered by terrorism statutes and are punishable by up to 20 years in jail and £15,500 fines. No-one has been arrested despite multiple attempts by police to serve warrants.
The Red Shirts include the rural and urban poor as well as pro-democracy advocates who see Oxford-educated Mr Abhisit as symbolic of an elite insensitive to the plight of most Thais.
Many are supporters of former prime minister and Manchester City FC owner Thaksin Shinawatra, a populist leader who was accused of charged with corruption and abuse of power and ousted in a 2006 military coup.