Supporters of Manuel Zelaya planned mass protests to mark the 90th day since the ouster of the Honduran president on Saturday, as hopes sunk of a rapid solution to the crisis.
Police officers stand guard as people demonstrate in support of Honduras' ousted President Manuel Zelaya in Tegucigalpa, Friday, Sept 25, 2009.
The deposed president remained holed up in the Brazilian embassy, along with around 60 people including supporters, journalists and diplomats, in increasingly uncomfortable conditions and surrounded by soldiers.
The UN Security Council on Friday warned the rebel authorities not to harass the embassy, as Zelaya claimed toxic gases had been pumped inside, causing people to vomit.
Chances for either side to change their positions looked increasingly slim.
Tensions rose after former rancher Zelaya made a surprise return on Monday, almost three months after soldiers sent him away at gunpoint amid a dispute over his plans to change the constitution.
Some 6,000 frustrated Zelaya supporters spilled onto the streets Friday, passing by rows of soldiers in front of the Brazilian embassy, ahead of larger demonstrations planned Saturday.
"Thanks, Brazil!" shouted some of the red-clad protesters.
Brazilian President Luiz Inacio Lula da Silva said Friday, speaking at the G20 summit in Pittsburgh, that Zelaya "could stay as long as necessary for his safety in the Brazilian embassy in Tegucigalpa."
Zelaya claimed Friday that noxious gases were being pumped into the embassy and called on the Red Cross for assistance.
"We have here some 60 people who are trying to breathe in the courtyard. There are people who are vomiting blood. A toxic gas has been disseminated," he told AFP in a phone interview.
A police spokesman categorically denied the use of gas.
In New York, the UN Security Council called for the protection of the Brazilian embassy at a emergency meeting.
Brazilian Foreign Minister Celso Amorim said the embassy was "virtually under siege."
The de facto leaders have insisted the compound will not be taken by force and denied they were responsible for initial power and water cuts.
They also underlined on Friday that they were not ready to meet with a delegation of diplomats hoping to help mediate the crisis.
"Honduran politics are not a threat to international peace and security, and, as a consequence, there should be a Honduran solution" to the stalemate, the foreign ministry said in a statement.
The previous day they said they would accept a visit by Costa Rican President Oscar Arias and Panama's Vice President Juan Carlos Varela as part of a mediation effort proposed by former US president Jimmy Carter.
But Arias told Costa Rican radio Friday that he was not planning "for the moment" to go to Honduras.
"The preliminary work needs to be done by the (foreign) ministers" of regional countries and representatives of the Organization of American States (OAS), Arias added.
The de facto leaders said late Friday they were postponing their invitation to the OAS mission.
There was no immediate comment from the pan-American body.
A daytime curfew was lifted Thursday and airports reopened, allowing businesses to resume and providing relief to an increasingly frustrated public. A nighttime curfew remained in place.
The United Nations on Wednesday froze its technical support for November's presidential poll, in which neither Zelaya nor Micheletti are standing. Zelaya's term ends in January.
A police spokesman told AFP Wednesday that two people had been killed in pro-Zelaya protests since the start of the week, and rights groups have voiced concern about clampdowns on demonstrators and local media.