As angry Aristide supporters armed with guns and machetes rampaged in the streets of the capital, Supreme Court chief justice Boniface Alexandre assumed interim power and appealed for calm.
Canadian special forces troops took control of the Port-au-Prince airport meanwhile and Haitian police resumed patrols in a bid to halt violence which erupted following Aristide's sudden departure.
Aristide, 50, increasingly isolated after months of bloody unrest in the Western hemisphere's poorest country, resigned early Sunday and fled to an as-yet unknown destination, officials said.
"My resignation will avoid bloodshed. Life for everyone, death for no one," Aristide, the firebrand priest turned politician, said in a farewell statement written in Creole and read by Prime Minister Yvon Neptune.
"I decided to respect and make people respect the constitution," Aristide added. "The constitution should not drown in the blood of Haitian people."
Aristide's constitutional successor Alexandre urged an end to the violence that has left dozens dead since the rebellion erupted three weeks ago.
"Haiti, I exhort you to remain calm. No one should take justice into their own hands," he said.
A top rebel leader, Guy Philippe, said the rebels surrounding Port-au-Prince were ready to lay down their weapons following the resignation of Aristide and would welcome the arrival of an international stabilisation force.
"We are ready to get rid of our weapons. We need an international force," Philippe said during a telephone interview with AFP from Haiti's second city, Cap-Haitien.
In Washington, US President George W. Bush urged Haitians to reject violence and said the United States stood by to help them.
"I would urge the people of Haiti to reject violence to give this break from the past a chance to work, and the United States is prepared to help," he said.
"I have ordered a deployment of Marines as the leading element of an interim international force to help bring order and stability to Haiti," Bush added.
A US defence official in Washington said a contingent of some 500 Marines could fly into Haiti as early as Sunday to assist with refugee repatriations by the US Coast Guard.
The official said the Marine contingent was not part of a multinational stabilisation force for Haiti but could be joined to such a force if one is deployed.
In Port-au-Prince, some 30 Canadian special forces soldiers secured the airport where three Canadian Hercules aircraft arrived earlier in the day to evacuate Canadian citizens, witnesses said.
Downtown, where pro-Aristide gangs had been rampaging, police were seen detaining looters and firing shots in the air to prevent arson and assaults on passerbys and journalists.
However, the security situation in many parts of the city and its suburbs remained volatile as random barricades, many of them made of flaming tires, continued to be manned by surly Aristide partisans who reacted with extreme anger to news of the president's departure.
Plumes of smoke continued to rise over sections of Port-au-Prince though the billowing black haze that had earlier hovered over the presidential palace - the result of a nearby house being set afire and a blazing gasoline station - had dissipated.
State Department spokesman Richard Boucher said the United States was seeking a UN Security Council resolution that would provide international support for a peaceful and constitutional transition of power in Haiti.
Boucher said that Caribbean Community (Caricom) nations, members of the Organisation of American States, Canada and France were being consulted.
"As envisaged under the Caricom plan, the international community will facilitate the urgent formation of an independent government that will represent the interests of all of the Haitian people," he said.
Aristide's exact whereabouts following his departure were unknown.
A US official said Aristide was aboard an aircraft heading for an unknown destination. "He is currently at 37,000 feet, give or take a couple of thousand," said the official who requested anonymity.