TEGUCIGALPA: Honduras sunk into further disarray afterPresident Manuel Zelaya, ousted in a military-backed coup, said a US-brokered deal to end the nation's four-month crisis had collapsed.

Presidential elections due on November 29 were in jeopardy as Zelaya called on his supporters to boycott them and return to the streets of the polarized nation.

Hundreds marched from the Congress to the Brazilian embassy, where Zelaya has been holed up since September 21, in a protest in the capital Friday.

Zelaya said last week's crisis deal was no longer valid after de facto leader Roberto Micheletti formed a new "national unity" government without his participation.

"The accord now has no value," Zelaya told AFP Friday.

Zelaya said there was no point continuing with negotiations because "the agreements have been constantly violated."

He also said that he had to "take some decisions," without elaborating. He said he had not decided whether he would stay in the Brazilian embassy until his term runs out on January 27.

The latest setback dealt a blow to foreign and US diplomats, including Secretary of State Hillary Clinton who had hailed last week's agreement as a triumph for democracy.

"We urge both sides to act in the best interests of the Honduran people and return to the table immediately to reach agreement on the formation of a unity government," State Department spokesman Ian Kelly said in Washington.

"We're disappointed that both sides are not following the very clear path laid out" in Costa Rican accords aimed at resolving the crisis, Kelly added.

The accord had given Zelaya and Micheletti's camps until midnight Thursday to set up a reconciliation government to represent both sides.

Although it did not require that Zelaya be reinstated, the pact said that decision should be left to Congress, without setting a deadline for the vote, which has not yet taken place.

Shortly before midnight, Micheletti announced a unity government without including Zelaya ministers.

The ousted leader had refused to present nominees for the posts unless he was first reinstated to "reverse the coup" of June 28.

The head of the Organization of American States, Jose Miguel Insulza, called Friday for Congress to make the decision on Zelaya's return and for the agreement to be met "without subterfuge."

Zelaya reiterated Friday that he would not back the November presidential polls.

"I'm not ready to legitimize a fraud ... nor to whitewash this coup," Zelaya said.

Foreign observers have said they will not take part until political stability is restored.

The European Union, the United States and multilateral agencies cut off vital foreign aid to protest the coup, and were supposed to restore it if the pact was fulfilled.

Many feared further social unrest after a heavy-handed crackdown by the de facto regime on protests by Zelaya supporters, including the media, in past months.

This week a grenade was detonated at a radio station seen as sympathetic to Micheletti, and two other grenade attacks were reported.

In a travel advisory, the State Department urged US citizens to "exercise caution" when traveling to Honduras, and to defer "all non-essential travel" to the capital Tegucigalpa until further notice.

The Supreme Court, Congress and business leaders backed the ouster of leftist Zelaya amid a dispute over his plans to change the constitution, which they saw as a bid to extend his single term.