A violent uprising has gripped northern parts of Haiti for two weeks as armed rebels seeking Aristide's ouster clash with his militant loyalists. At least 57 people have died.
The U.S. State Department on Thursday urged Americans to leave the country "while commercial carriers are still operating on an uninterrupted schedule." The department warned those remaining in the country that the U.S. Embassy's ability to assist U.S. citizens is very limited.
About 20,000 Americans, a quarter of them missionaries, are registered with the embassy, according to the Associated Press.
The Pentagon is sending a four-man military team to assess the security of the U.S. Embassy in the capital, Port-au-Prince, in the southern part of the country. The embassy has imposed a nighttime curfew on its employees and families, and restricted travel outside Port-au-Prince.
The department said the Peace Corps has ordered its staff to leave Haiti until the situation stabilizes.
Armed rebels have taken more than a dozen towns since the uprising began Feb. 5 in Gonaives, northwest of Port-au-Prince.
The U.S. government has rejected the idea of sending troops to Haiti, instead favoring a political solution.
Toward that end, the United States, Canada, France, and Latin American and Caribbean nations crafted a plan that calls on Aristide to appoint a new government, strengthen the police and release detainees, while requiring that his opponents disarm and enter a political dialogue.
"The bottom line is, we have to see the formation of a new government that will perform fully its constitutional role," a State Department official told The Washington Post. The government must "be able to inspire confidence by virtue of its composition and independence," he said.
Assistant Secretary of State Roger Noriega will be the U.S. representative on the mission, according to the Post.
Secretary of State Colin Powell said Aristide's resignation is not part of the plan but left open the possibility that the president might step down in a negotiated settlement.
Aristide has rejected the notion of leaving before his term expires in February 2006.
"I am ready to give my life if that is what it takes to defend my country," he said at a memorial service for slain police officers Thursday in Port-au-Prince.
Aristide became Haiti's first elected leader in 1990, but was ousted in a coup and then reinstated with U.S. help in 1994. He won a second term as president in 2000, but many said legislative elections held that year -- that his Lavalas Party swept -- were flawed.
The political stalemate caused many international donor groups to withhold funding, making Aristide unable to deliver on some of his election promises, contributing to discontent in the country.
U.S. relations with Aristide have become strained, with U.S. officials challenging what they say is his uncompromising style and rule by intimidation.
The State Department's recent travel warning blames antigovernment groups for starting the violence, but says Haiti's security problems stem from Aristide's continued politicization of the Haitian National Police and use of government resources to pay "violent gangs to attack opposition demonstrators."