Soldiers seized the national palace and flew President Manuel Zelaya into exile Sunday, hours before a disputed constitutional referendum. Congress appointed a successor, but Zelaya, a leftist ally of Venezuelan President Hugo Chavez, said he was the victim of an illegal coup.
Hours later, Congress voted to accept what it said was Zelaya's letter of resignation and by a show of hands, voted to appoint congressional President Roberto Micheletti as the new chief executive.
But Zelaya said the letter wasn't his and vowed to remain in power.
The Supreme Court said it was supporting the military in what it called a defense of democracy.
Zelaya was arrested shortly before polls were to open in a referendum on whether to change the constitution. The Supreme Court ruled the referendum illegal and everyone from Congress to members of his own party opposed it. Critics said Zelaya wanted to remove limits to his re-election.
Tanks rolled through the streets and hundreds of soldiers with riot shields surrounded the presidential palace in the capital, Tegucigalpa. Zelaya, at the airport in the Costa Rican capital, San Jose, called the military action illegal.
"There is no way to justify an interruption of democracy, a coup d'etat," he said in a telephone call to the Venezuela-based Telesur television network. "This kidnapping is an extortion of the Honduran democratic system."
A majority of members of Congress voted with a show of hands to accept a letter of resignation that Congressional Secretary Jose Alfredo Saavedra said was signed by Zelaya and dated Thursday. The letter said Zelaya was resigning because of "the polarized political situation" and "insuperable health problems."
A resolution read on the floor of Congress accuses Zelaya of "manifest irregular conduct" and "putting in present danger the state of law," a reference to his refusal to obey a Supreme Court ruling against holding a constitutional referendum.
But Zelaya told Telesur he would not recognize any de facto government and pledged to serve out his term, which ends in January. He said he would attend a scheduled meeting of Central American presidents in Nicaragua on Monday. He said Chavez, who is also going, would provide transportation.
Chavez, who along with the Castros in Cuba is Zelaya's top ally, said Venezuela "is at battle" and put his military on alert.
President Barack Obama said he was "deeply concerned" by Zelaya's expulsion and U.S. Secretary of State Hillary Clinton said the arrest should be condemned.
"I call on all political and social actors in Honduras to respect democratic norms, the rule of law and the tenets of the Inter-American Democratic Charter," Obama's statement read.
Zelaya told Telesur that he was awoken by gunshots and the shouts of his security guards, whom he said resisted troops for at least 20 minutes. Still in his pajamas, he jumped out of bed and ducked behind an air conditioner to avoid flying bullets, he said.
He said eight or nine soldiers in masks escorted him onto an air force plane that took him to Costa Rica.
Chavez said troops in Honduras also temporarily detained the Venezuelan and Cuban ambassadors, beating them.
Zelaya called on Honduran soldiers to desist, urged citizens to take to the streets in peaceful protests, and asked Honduran police to protect demonstrators.
Zelaya ally Rafael Alegria, a labor leader, called for protests.
"We demand respect for the president's life," he told Honduran radio Cadena de Noticias. "And we will go out into the streets to defend what this has cost us: living in peace and tranquility."
About 100 Zelaya supporters, many wearing "Yes" T-shirts for the referendum, blocked the main street outside the gates to the palace, throwing rocks and insults at soldiers and shouting "Traitors! Traitors!"
"They kidnapped him like cowards," screamed Melissa Gaitan. Tears streamed down the face of the 21-year-old, who works at the government television station. "We have to rally the people to defend our president."
Honduras has a history of military coups: Soldiers overthrew elected presidents in 1963 and 1972. The military did not turn the government over to civilians until 1981, under U.S. pressure.
Micheletti has been one of the president's main opponents in the dispute over whether to hold the referendum. The head of the Supreme Court was also opposed to the nonbinding referendum, on whether to ask voters whether they want to convoke an assembly to rewrite the constitution.
It appeared that the vote would no longer take place.