Haitian rebels have moved closer to the capital Port-au-Prince with the capture of Mirebalais, a town just 60km away.
Rebels continue to threaten an attack on the capital
Law and order in the capital has broken down, as supporters of President Jean-Bertrand Aristide barricade the streets in preparation for a final stand.
The French foreign minister on Friday apparently added his voice to growing pressure on Mr Aristide to resign.
Three US naval vessels have been put on standby to go to Haiti as a precautionary measure, officials said.
Defence officials told the BBC that the ships - with the potential to carry 2,000 marines - would be used to evacuate of US embassy staff and other citizens if deployed.
But they stress no decision has yet been made.
BBC Pentagon correspondent Nick Childs says there is no appetite either in the Pentagon or the Bush administration for direct intervention in the crisis in Haiti unless there is a political settlement first.
The rebels, who have overrun most of the north with little prolonged resistance in recent weeks, have now virtually cut off the capital.
One rebel leader, Guy Philippe, has said he wants to celebrate his 36th birthday on Sunday in Port-au-Prince.
The rebellion now also appears to have infected the south, with the seizure by separate rebels of Haiti's third-largest city, Les Cayes.
In Port-au-Prince, belligerent armed supporters of the president have set up barricades across the city and are vowing to defend the presidential National Palace, though it is not known whether Mr Aristide is inside.
One of them was quoted as saying: "[The rebels] say they are coming. So we are waiting for them."
The bodies of 10 or 12 victims of the disorder can be seen lying in the streets, and most residents have retreated indoors.
There has been widespread looting, with reports that equipment worth hundreds of thousands of dollars has been stolen from the city's port.
But some of the looting is being done by desperate Haitians, who have been denied access to basic necessities by poverty and the unrest, says the BBC's Claire Marshall.
French Foreign Minister Dominique de Villepin met a Haitian government team led by Foreign Minister Joseph Philippe Antonio for an hour on Friday.
The suspension of Air France flights to Haiti prevented any Haitian opposition representatives going too.
A spokesman for Mr de Villepin said he proposed a "government of national unity" without Mr Aristide to be put in place.
"It's for President Aristide, who bears a heavy responsibility in the current situation, to draw the conclusions from the impasse," said the ministry in a statement afterwards.
Supporters of the president have gathered outside the National Palace
The Haitian delegation left without commenting.
On Thursday, US Secretary of State Colin Powell said Mr Aristide had had "difficulties" in his presidency including corruption, cronyism and inefficiency.
"Whether or not he is able to effectively continue as president is something he will have to examine carefully in the interests of the Haitian people," he told reporters.
The United Nations refugee agency, UNHCR, has renewed its call for Haiti's neighbours to grant asylum to people fleeing the ongoing crisis there.
Earlier, the US Coastguard said it had intercepted some 500 people in boats fleeing Haiti in the past few days.
President Bush has warned Haitians they will be sent home if they try to flee to the US.