TEGUCIGALPA, Honduras — Diplomatic efforts to restore Manuel Zelaya to Honduras' presidency shifted back to Washington on Tuesday, as supporters of the ousted leader threatened to escalate protests and disrupt business across the poor Central American nation.

A day after failing to land in Honduras to confront the interim government that ousted him in a coup, Zelaya boarded a plane bound for Washington, where U.S. officials said he would meet with Secretary of State Hillary Clinton.

Zelaya told a news conference Monday night that he hopes to ensure U.S. support for diplomatic efforts to see him restored to power.

"Tomorrow we hope to get support for these pronouncements," Zelaya said before heading to the airport in Managua.

The talks come as the Obama administration weighs how to respond to the military coup that sent Zelaya into exile June 28. The U.S. government is looking for a peaceful resolution, and senior officials said Washington tried to dissuade Zelaya from Sunday's attempt to fly into the Tegucigalpa airport, which led to clashes between the army and his supporters.

"We're very focused on the need for a dialogue to restore him back (to office) and restore the democratic order," State Department spokesman Ian Kelly said.

As Zelaya left nearby Nicaragua on Monday, 2,000 of his supporters rallied peacefully near the presidential palace in the Honduran capital. But anger was high over the death of a teenager shot by soldiers Sunday as a crowd tried to break through the airport's perimeter fence, before Zelaya's plane gave up on trying to land because army vehicles blocked the runway.

"We're going to change strategies," protest organizer Rafael Alegria, 57, said Monday. "We cannot live under the current state."

He said Zelaya's supporters would take their fight nationwide by blocking major highways and border crossings in an effort to impede trucks delivering fuel and merchandise.

The interim government — named by Congress to replace Zelaya's administration after a fight over his effort to stage a constitutional referendum that the Supreme Court ruled illegal — remained steadfast in saying he would not be allowed to return. It formally closed the airport Monday, and military vehicles and an old plane blocked the runways.

Zelaya is opposed by all branches of the Honduran government as well as the military. He even alienated leaders of his own party, which supported a congressional vote to install congressional leader Roberto Micheletti as interim president.