The United States has warned Haitian President Jean-Bertrand Aristide to rein in pro-government gangs.
Deadly violence, looting and chaos broke out in Port-au-Prince
In a statement, the US administration also called on the rebels to halt their advance on the capital, Port-au-Prince.
Haitian rebels have moved closer to the city on Friday with the capture of Mirebalais, a town just 60km away.
Law and order in the capital has broken down, as supporters of President Aristide barricade the streets in preparation for a final stand.
In a statement, the US embassy in Port-au-Prince called on the Haitian president to control his supporters and what it described "blind violence against the civilian population".
Honour at stake
The statement said armed gangs, declaring their support for Mr Aristide, have been on the rampage, looting and murdering apparently innocent civilians in the capital.
"The armed gangs that are spreading terror and attacking civilians and the general population are acting in the name of Jean Bertrand Aristide."
The US administration has asked Mr Aristide to issue necessary instructions to his supporters to stop the chaos.
It says. "Mr Aristide must understand that his honour, legacy and reputation are at stake."
It also calls on the rebels that are poised to attack the capital to stop their advance to spare the city from further violence.
The BBC's Stephen Gibb in the Haitian capital says the call appears to have been heeded with one of the rebels saying his current strategy is to blockade the city and thus force Mr Aristide to resign.
But he says, the president shows no sign of leaving.
The president says he had a responsibility to stay in office and protect his people despite the rebel gains and international pressure to step down.
With the taking of Mirabalais, the rebels now control all Haiti's major cities, with the exception of Saint Marc 96km (60 miles) from the capital.
One rebel leader, Guy Philippe, has said his forces would soon be in Saint Marc before entering Port-au-Prince.
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.