Zelaya, who was forced into exile in a June 28 military coup, gave negotiators meeting in Costa Rica until midnight to restore him to office, threatening to return to Honduras in secret and attempt to retake power on his own if no agreement is reached. He indicated he would reject any power-sharing agreement, a proposal to be discussed at the talks.
"If at that time, there is no resolution to that end, I will consider the negotiations in Costa Rica a failure," Zelaya said at a news conference Friday night at the Honduran embassy in Nicaragua. "I am going back to Honduras, but I am not going to give you the date, hour or place, or say if I'm going to enter through land, air or sea."
He did not say what steps he would subsequently take. But earlier this week, he said Hondurans have a constitutional right to rebel against an illegitimate government. His foreign minister, Patricia Rodas, said Thursday that if the talks failed, Zelaya would return to Honduras to install a parallel government "to direct what I will call the final battle."
The interim government has vowed to arrest Zelaya if he returns. The military thwarted his attempt to fly home July 5 by using vehicles to block the runway, preventing his plane from landing in the Honduran capital, Tegucigalpa.
Zelaya's allies said the Costa Rica talks might be the last chance to avert a clash, perhaps even civil war in the impoverished Central American country. Zelaya supporters have staged near daily protests demanding his return, including about 2,000 who blocked two highways connecting Tegucigalpa to the Caribbean and Pacific coasts for several hours Friday.
Costa Rican President Oscar Arias, who is mediating the talks, had appeared optimistic about a resolution earlier Friday, saying both camps had "softened, and I think we are going to find more flexibility." In the first round of talks the two sides agreed only to meet again.
Arias, who won the Nobel Peace Prize in 1987 for helping to end Central America's wars, has presented a series of possible compromises to both camps, including a power-sharing deal in which Zelaya could return to serve out the remaining months of his term as president, but with limited power.
Zelaya suggested he would reject such a plan. "I cannot accept a reward for the coup leaders because that would be an aberration," he said.
Arias also said an amnesty deal for Zelaya was possible.
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.
Many Hondurans viewed the proposed 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.
In Washington, U.S. State Department spokesman P.J. Crowley called Friday for all nations to support the talks.