Zelaya accused his opponents of "making a mockery" of Costa Rican President Oscar Arias' attempts to mediate an agreement and called for stronger international pressure on the government of Roberto Micheletti, the interim president sworn in by Honduras' congress after a June 28 coup.

Singling out the United States repeatedly, Zelaya said the international community risks tacitly endorsing the putsch if it does not confront the interim government that abducted and deposed him at gunpoint.

"The international community is facing a dilemma," Zelaya told reporters at the Honduran Embassy in the Nicaraguan capital late Sunday. "They asked the guerrilla movements 20 years ago to put down their arms. ... And now the conservatives come back and take up arms to boot out the leftists who are attempting a process of reform."

Arias, the 1987 Nobel Peace Prize laureate for brokering an end to Central America's civil wars, proposed a plan that would let Zelaya serve out the final months of his term, move up elections by one month to late October, grant a general amnesty and include representatives of the main political parties in a reconciliation government.

The Micheletti government endorsed several of those proposals on Sunday -- but his foreign relations secretary, Carlos Lopez, rejected the overall plan, specifically citing the issue of Zelaya's return to power.

A counterproposal suggested Zelaya could return as a regular citizen -- to be tried in court. Honduras' Supreme Court issued an arrest warrant for Zelaya before the coup, ruling that his effort to hold a referendum on calling for a constitutional assembly was illegal.

Many Hondurans viewed the referendum as an attempt by Zelaya to push for a socialist-leaning government similar to the one his ally Hugo Chavez has established in Venezuela.

Zelaya, a wealthy rancher who shifted left during his presidency, charged that the current constitution protects a system of government that excludes the poor.

The aftermath of the coup is turning into a major test of Latin American democracy and of the Obama administration's policy toward the region.

The U.S., the United Nations and the Organization of American States have demanded that Zelaya be reinstated, and no foreign government has recognized Micheletti.

In Washington, OAS chief Jose Miguel Insulza said Sunday that the international community continues to support Zelaya's return to power, and the Micheletti government needs to confront that reality.

"This is a coup that failed," Insulza told a news conference.

But further isolating impoverished Honduras, even Zelaya's allies concede, puts the country's stability at further risk.

Arias promised further efforts to seek a solution, and Vilma Morales, a negotiator for the interim government, said talks could resume Wednesday.

"Dialogue is not broken," she told the AP.

Zelaya, who previously vowed to go back to Honduras and set up a parallel government if the talks failed, left open the possibility that talks could bear fruit. But he said he would push forward with organizing "resistance" inside Honduras to prepare for his eventual return. He did not give details.

The Honduran military thwarted Zelaya's first attempt to fly home on July 5 by blocking the runway at the airport in the capital, Tegucigalpa.

"Next weekend we will have everything necessary to make our return," he said late Sunday in Managua. "The social pact in Honduras is broken; the military broke it."When asked about the idea of having Zelaya return to Honduras as president with a reconciliation government, Assistant Foreign Minister Martha Lorena Alvarado gave a one-word response: "Impossible."

Her comment in Honduras' capital, Tegucigalpa, was the clearest indication that the talks had deadlocked.

"The reinstatement of Zelaya, as we have maintained and now repeat, is not negotiable ... there is no possibility of him returning to Honduras as president," Alvarado said.

Before Alvarado's rejection, a representative of Honduras' interim government said her delegation lacked the authority to accept most of Arias' proposals, since decisions on amnesty, changed election dates and permission for Zelaya to return despite warrants for his arrest needed the approval of Honduras' courts or Congress.

"It is up to Congress to grant amnesties, so we cannot commit to something that intrudes on the powers of other bodies," former Supreme Court President Vilma Morales told The Associated Press. "We cannot make commitments that ignore the jurisdiction of the electoral tribunal, and it is also up to Congress to discuss and legislate and issue a decree on moving up the elections."

Zelaya's supporters have staged near daily protests demanding his return, and about 3,000 blocked traffic on one of the main boulevards in the capital Saturday chanting slogans in favor of the ousted leader.

"Nothing will come out of the negotiations and people know that," said Cesar Silva, who helped organize the protest. He said he expected Zelaya to return to Honduras after midnight Saturday.

About 300 Zelaya supporters chanted slogans outside Arias' house as the meeting started.

"These negotiations have been put together to legitimize the coup government and all they are looking for is an exit that doesn't include their punishment or reinstating Zelaya," said John Vega, a Costa Rican student.

Honduras' Supreme Court issued an arrest warrant for Zelaya before the coup, ruling his effort to hold a referendum on whether to form a constitutional assembly was illegal. The military decided to send Zelaya into exile instead a move that military lawyers themselves have called illegal but necessary.