About 30 Canadian special forces soldiers secured the airport on Sunday and two sharpshooters positioned themselves on the top of the control tower after three Canadian aircraft arrived to evacuate Canadians, RDI television said.
"I have ordered the deployment of Marines as the leading element of an interim international force to help bring order and stability to Haiti," Bush told reporters in Washington.
Criticised for responding slowly to defuse the revolt and for failing to mediate a viable alternative to Aristide, Washington was worried rebels would fill a power vacuum in a nation with a history of coups and political violence.
Alexandre sworn in
Earlier in the day, Haitian Chief Justice Boniface Alexandre was sworn in as president to replace Aristide, who resigned in the face of an armed revolt and fled the country to neighbouring Dominican Republic.
He is now on his way to Morocco, the Haitian consul in the Dominican Republic said.
Alexandre, an Aristide appointee, is president of Haiti's Supreme Court and is designated by Haiti's constitution to temporarily assume the presidency if the office becomes vacant.
Aristide resigned in the face of
Morocco has said it would not grant the Haitian president asylum.
"The kingdom of Morocco has no intention of responding favourably to an eventual demand granting political asylum to President Aristide in Morocco," said the official MAP news agency, quoting a Foreign Ministry statement.
Meanwhile, in downtown Port-au-Prince where pro-Aristide gangs had been rampaging, Haitian police were seen detaining looters and firing shots in the air to prevent arson and assaults on passersby and journalists, the witnesses said.
Nevertheless, the security situation in many parts of the city and its suburbs remained volatile on Sunday, 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, although a 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.