The US State Department said it was ready to take further measures after already halting most visa services in Honduras, revoking visas for the interm regime and suspending 35 million dollars in military aid.
"We obviously have other steps that we can take," State Department spokesman P.J. Crowley said. "I think we'll make some decisions in the next couple of days."
A State Department official, speaking on condition of anonymity, said the United States was looking at suspending assistance through the Millennium Challenge Corporation, which rewards nations with free economies and political systems.
Honduras in 2005 signed a five-year, 215 million-dollar deal with the US government-funded corporation to boost agriculture and transportation.
The funds are helping to widen and upgrade the Central American nation's principal highway, the CA-5, a project the corporation says will benefit hundreds of thousands of Hondurans.
According to the latest quarterly report, some 80.3 million dollars has been disbursed, meaning that the US government could block some 135 million dollars that is in the pipeline.
The United States would cut off the aid by formally declaring that Honduras has undergone a military coup and that it sees little chance of the regime changing course.
The State Department has recommended such a move, but it is awaiting final approval by Secretary of State Hillary Clinton, the State Department official said.
The strategy is seen as partly an attempt to contain the influence of Venezuela's firebrand leftist President Hugo Chavez, an ally of Zelaya who in the past has vociferously attacked the US role in Latin America.
Under a proposal drawn up by Costa Rican President Oscar Arias, Zelaya would return to power but new elections would be held promptly and those who participated in the coup would enjoy an amnesty.
In a statement, the State Department said that both interim leader Micheletti and Zelaya -- who supports the deal -- "would be well advised to sign it promptly."
"The United States supports the peaceful restoration of democratic and constitutional order in Honduras with President Zelaya?s return as president to finish his term," the State Department said in a statement to AFP.
Jose Miguel Insulza, the head of the Organization of American States who led the mission to Tegucigalpa, warned Wednesday that the window for a negotiated settlement will close as Honduras' scheduled November 28 elections approach.
Micheletti has insisted that his de facto government would step down after elections, for which campaigning opens next week.
But Insulza warned that many countries in the region would not recognize the outcome.
In Tegucigalpa, a coalition of labor unions, teachers, activists and others opposed to the coup vowed to boycott the elections unless Zelaya returns to power.
"We've organized neighborhoods in the capital and in all the towns of the country so as not to let in any candidates from the oligarchy," opposition leader Alejandro Casco told AFP in Tegucigalpa.
Source: AFP Global Edition