"I am going to Tegucigalpa on Thursday," Zelaya said, although he did not give details of how he intended to return. "The president elected by the people is coming."
The leftist president was ousted at gunpoint in a military coup Sunday and flown into exile in Costa Rica. Congress named Roberto Micheletti, a more conservative member of Zelaya's own party, as interim president.
Governments worldwide, including the U.S. and nearly all of Honduras' Latin American neighbors, have denounced the coup and voiced support for Zelaya.
In Tegucigalpa, at least 1,500 protestors, some armed with rocks, bottles and sticks, demonstrated and burned tires in the streets. The military responded with tear gas, and dozens were injured in the clashes.
"We are going to be here until President Zelaya returns. Micheletti is the president of the rich and powerful in this country," a 22-year-old electrician who gave his name as Kevin told Reuters.
Meanwhile, governments around the world denounced the coup. Left-wing presidents, led by Venezuelan president Hugo Chavez, announced at a meeting in Nicaragua that they would withdraw their ambassadors from Honduras. Conservative Mexican president Felipe Calderon followed, and Brazil told its ambassador, who was out of the country at the time of the coup, not to return until further notice.
President Barack Obama also voiced support for Zelaya, calling the coup a "terrible precedent."
"We do not want to go back to a dark past," he said, referring to decades of Latin American military coups. "We always want to stand with democracy."
The administration strongly denied charges that the U.S. turned a blind eye to the impending coup. The U.S. has a long history of supporting coups in Latin America and has close ties to the Honduran military. But Obama's quick denouncement of the coup differed from the Bush administration's tacit endorsement of a failed 2002 overthrow attempt of Venezuelan president Chavez.
And administration officials told the New York Times that while they knew of impending tensions in the country, they did not expect the military to attempt a coup, saying that discussions were focusing on legal maneuvers to remove the president.
"There was talk of how they might remove the president from office, how he could be arrested, on whose authority they could do that," an anonymous administration official told the paper.
Tensions had grown in Honduras over Zelaya's recent efforts to hold a referendum to amend the constitution to allow presidents to run for reelection beyond a single four-year term. Zelaya, a wealthy rancher and logger, had grown close to Chavez and had steered the country leftward since his election in 2006, and opponents feared it was heading toward Chavez-style socialism.
"President Zelaya was moving the country toward Chavismo, he was following this model which is not accepted by Hondurans," Micheletti told Reuters. "Honduras is more of a democracy today than it was three days ago."
Micheletti said that previously scheduled elections will take place in November as planned.
"We respect the whole world, and we only ask that they respect us and leave us in peace," he said.
The last successful coup in Latin America occurred in 1993, in Guatemala. Honduras last saw a coup in 1978.