Police and soldiers blanketed the streets of the capital early Monday, enforcing a sunset-to-sunrise curfew with batons and metal poles. Civil aviation authorities announced a 24-hour ban on all flights at the country's main airport starting Monday morning.
Soldiers clashed Sunday with thousands of Zelaya backers massed at the airport in hopes of welcoming home the deposed leader removed a week earlier.
But military vehicles and soldiers blocked the runway. Pilots of the plane loaned by Venezuelan President Hugo Chavez circled the airport and decided not to risk a crash.
Zelaya instead headed for El Salvador, and vowed to try again Monday or Tuesday in his high-stakes effort to return to power in a country where all branches of government have lined up against him.
Zelaya is banking on the confrontation keeping the pressure on the new Honduran government, reported CBS News correspondent Kimberly Dozier.
"I call on the Armed Forces of Honduras to lower their rifles," he said late Sunday at a news conference, flanked by the presidents of El Salvador, Argentina, Paraguay and Ecuador, and the secretary-general of the Organization of American States, Jose Miguel Insulza, who flew there from Washington.
"I am risking myself personally to resolve the problems without violence," said Zelaya, who planned to fly later to Nicaragua. He urged the United Nations, the OAS, the United States and European countries to "do something with this repressive regime."
Insulza said he "is open to continuing all appropriate diplomatic overtures to obtain our objective."
But interim Honduran President Roberto Micheletti said he won't negotiate until "things return to normal."
"We will be here until the country calms down," Micheletti said. "We are the authentic representatives of the people."
U.N. Secretary-General Ban Ki-moon said Monday in Geneva he is saddened by the loss of life in Honduras and he urged authorities to protect civilians, saying they should be allowed to express their opinions without being threatened.
He again called the coup unacceptable.
Clashes broke out Sunday afternoon between police and soldiers and the huge crowd of Zelaya supporters surrounding Tegucigalpa's international airport. At least one man was killed - shot in the head from inside the airport as people tried to break through a security fence, according to an Associated Press photographer at the scene.
The Red Cross identified him as a 19-year-old from Zelaya's home province of Olancho.
At least 30 people were treated for injuries, the Red Cross said, after security forces fired warning shots and tear gas.
When Zelaya's plane was turned away, his supporters began chanting "We want blue helmets!" - a reference to U.N. peacekeepers.
Karin Antunez, 27, was in tears.
"We're scared. We feel sad because these coup soldiers won't let Mel return, but we're not going to back down," she said, referring to Zelaya by his nickname. "We're the people and we're going to keep marching so that our president comes home."
Zelaya won wide international support after his ouster, but several presidents who originally were to accompany him decided it was too dangerous to fly on Zelaya's plane, which carried only close advisers, two journalists from the Venezuela-based network Telesur and U.N. General Assembly President Miguel D'Escoto Brockmann, a leftist Nicaraguan priest and former foreign minister.
Honduras' new government has vowed to arrest Zelaya for 18 alleged criminal acts including treason and failing to implement more than 80 laws approved by Congress since he took office in 2006. Zelaya also refused to comply with a Supreme Court ruling against his planned referendum on whether to hold an assembly to consider changing the constitution.
Critics feared Zelaya might try to extend his rule and cement presidential power in ways similar to what his ally Chavez has done in Venezuela - though Zelaya denied that.
But instead of prosecuting him or trying to defeat him at the ballot box, masked soldiers flew the president out of the country at gunpoint, and Congress installed Micheletti in his place.
The military solution drew international condemnation, and Honduras was suspended by the OAS. Many called the coup a huge step backward for democracy, and no nation has recognized the new government. President Barack Obama has united with Chavez and conservative Colombian President Alvaro Uribe in insisting on Zelaya's return.
Speaking on condition of anonymity under ground rules set by the State Department, senior U.S. officials said the United States and other OAS member countries are coordinating contacts to facilitate a resolution, despite their insistence on having no formal relations with the interim government.
Without OAS membership, Honduras faces trade sanctions and the loss of hundreds of millions of dollars in subsidized oil, aid and loans for the impoverished nation.
Moments after Zelaya's plane was turned away, trucks filled with police ordered everyone off the streets.
"This is a war," said Matias Sauceda, 65, a human rights activist. "Imagine - things are so bad, that the president is in the air and they don't let him land."