The US state department has urged all Americans in Haiti to leave the country because of the continuing unrest there.
The violent uprising has claimed more than 50 lives
Washington also said a small military team would be sent to Haiti to ensure the security of the US embassy there.
Secretary of State Colin Powell said the US was working with other countries on a plan to end the row between rebels and the president.
President Jean-Bertrand Aristide has reaffirmed his intention to remain in office, despite calls for him to go.
More than 50 people have been killed in uprisings by rebels calling for his resignation.
Mr Powell said the US - working with the United Nations, Organisation of American States (OAS), France and other countries - would be offering a proposal to both Mr Aristide and opposition leaders to try and resolve the crisis.
He gave no details of the plan except to say that it did not require the president to step down.
"I think if they will both accept this plan and start executing on it, we might find a way through this crisis politically," Mr Powell told ABC Radio's Live in America programme on Thursday.
The OAS has already passed a resolution calling on President Aristide to respect human right and comply with proposals put forward by other Caribbean nations to end the unrest.
The US travel warning strongly urged all American citizens to leave Haiti while commercial carriers were still operating.
Aristide vows to serve the remaining two years of his time in office
Citing what it called a steady deterioration of the security situation in the country, it said those Americans choosing to stay should remain vigilant.
And in a further sign of decreasing confidence in Haiti's stability, the Pentagon said a team of three or four personnel would be in Haiti in the next couple of days or so.
But Pentagon officials insisted that the team's mission would be strictly limited at this stage, and would focus mainly on security at the US embassy itself and the safety of US officials there.
Pentagon spokesman Lawrence DiRita said the US ambassador in Haiti, James Foley, had asked for such a team.
And US defence officials cautioned against seeing the move as a precursor to any wider military intervention.
The BBC's Nick Childs says there is clearly little appetite at the Pentagon for this.
On Thursday, Mr Powell said the US would not object if President Aristide chose to stand down, but only if it was done constitutionally and as part of a negotiated political deal.
"He is the president for some time to come yet," said Mr Powell. "Now, if an agreement is reached that moves that in another direction, that's fine."
But at a ceremony to honour policemen who had died in the uprising, a combative President Aristide made it clear he did not intend to go quietly.
"I, too, am ready to die if that is what I must do to defend my country," said the president, who has survived three assassination attempts and a coup d'etat.
"If wars are expensive, peace can be even more expensive," he added.
He described his government as defending democracy against a band of terrorists.
Armed rebels now control several towns in the north of the country, and are threatening to attack its second largest city.
In the capital, Port-au-Prince, there has been another demonstration by students calling for Mr Aristide to stand down.