"The Brazilian government is gravely concerned that the same people who perpetrated the coup d'etat in Honduras might threaten the inviolability of the embassy in order to forcefully arrest President Zelaya," he said.

Susan Rice, the US ambassador to the United Nations, called on the Honduran government to "cease harassing the Brazilian mission".

Luiz Inacio Lula da Silva, Brazil's president, said on Friday that Zelaya can remain inside the embassy for as long as he chooses.

Embassy surrounded

Hundreds of Honduran soldiers and riot police are surrounding the Brazilian embassy compound, where Zelaya is holed up with his family and about 40 supporters.

Country profile

  Second largest country in Central America
  Population of 7.2 million
  Second poorest country in the region
  Economy forecast to grow less than two per cent this year
  Relies on money from Hondurans in the US for more than 25 per cent of its gross domestic product
  Former Spanish colony gained independence in 1821

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Honduras poor pay price of coup crisis
Local media reported on Friday that some people inside the embassy compound had been sickened by gas, Al Jazeera's Mariana Sanchez said.

"There were reports from the embassy that there was some kind of chemical in the air that had caused some of the people inside the embassy to start bleeding," she said from Tegucigalpa.

"The Red Cross came here to verify this but the army would not let them through. Then, the chief of police came here and denied that the military had thrown any kind of gas inside the building.

"We have spoken to someone inside the embassy compound who said that there was a minor gas leak."

Zelaya later accused police of using toxic gases to poison those inside, causing headaches and nose bleeds.

"We'll take this to mean clearly they don't want to hold any dialogue," he said.

Zelaya, who re-entered his country on Monday after three months in exile, said on Friday that that his supporters should come to Tegucigalpa to exert pressure on Roberto Micheletti, the de facto president.

"We urge the resistance to keep fighting until together the people and president achieve ... the fall of the usurpers," Zelaya said.

"We see no willingness on the part of the de facto government to reinstate the president."

Mediation effort

The deposed president said on Thursday that he had held talks with a member of the de facto government, but that little progress was made.

The de facto government on Thursday said they would accept a visit by Oscar Arias, the Coasta Rican president, and Juan Carlos Varela, Panama's vice-president, as part of a mediation effort.

The Honduran foreign ministry asked the Organisation of American States (OAS) to postpone its own mediation mission until talks with Arias had concluded.

The United States, the European Union and the OAS have each condemened the overthrow of Zelaya, which came after Zelaya attempted to hold a referendum on presidential term limits.

Micheletti says that Zelaya has to answer charges of violating the constitution through his move to hold a non-binding referendum without the assent of the Honduran courts and parliament.

Zelaya has said that the referendum was not aimed at winning support to extend his single term in power, and that it was part of a move to provide more representation to the poor.