Port-au-Prince, Haiti ? Haiti’s prime minister warned Tuesday of an impending coup and appealed for international help to contend with a bloody uprising that has claimed 57 lives. But the United States and France expressed reluctance to send troops to put down the rebellion.

Aid agencies called for urgent international action, warning Haiti is on “the verge of a generalized civil war.” The U.N. refugee agency met with officials in Washington to discuss how to confront a feared exodus of Haitians.

On Tuesday, airlines in Port-au-Prince canceled flights to the northern port of Cap-Haitien, Haiti’s second-largest city, after witnesses in the barricaded city saw a boat approach and rumors swept the town that rebels were about to attack.

In the western port of St. Marc, an American missionary said his life had been threatened by supporters of President Jean-Bertrand Aristide.

“We are witnessing the coup d’etat machine in motion,” Prime Minister Yvon Neptune said Tuesday, urging the international community “to show it really wants peace and stability.”

Haiti’s 5,000-member police force appears unable to stem the revolt, but Aristide and Neptune stopped short of asking for military intervention.

Secretary of State Colin Powell said Tuesday “there is frankly no enthusiasm right now for sending in military or police forces to put down the violence.”

Powell said the international community wanted to see “a political solution” and only then would willing nations offer a police presence to implement such an agreement.

Powell spoke by telephone with French Foreign Minister Dominique de Villepin, who called an emergency meeting Tuesday in Paris to weigh the risks of sending peacekeepers and discuss how otherwise to help Haiti, an impoverished former colony that is home to 2,000 French citizens.

“We have to reflect on what we can do, for example, in the framework of the Security Council,” de Villepin said.

The United States has staged three military interventions in Haiti, the last in 1994, when it sent 20,000 troops to end a military dictatorship that had ousted Aristide and halt an influx of Haitian boat people to Florida.