The de facto government of Honduras denied entry on Sunday to an Organization of American States delegation and threatened to close Brazil's embassy, where ousted President Manuel Zelaya has taken refuge, Reuters reported.
The group of OAS officials had hoped to help broker a solution to Honduras' political crisis but was turned back at Tegucigalpa's international airport, a move likely to further isolate the government headed by Roberto Micheletti.
Hours earlier, Brazilian President Luiz Inacio Lula da Silva said he would ignore a 10-day deadline set by Micheletti to decide what to do with Zelaya, who is holed up with his family and some supporters in Brazil's embassy in the capital.
"Brazil will not comply with an ultimatum from a government of coup mongers," Lula told reporters at a summit of African and South American leaders in Venezuela.
Lula also demanded an apology from Micheletti, who issued a harsh statement late on Saturday warning that his government would be forced to take action if Brazil does not define Zelaya's status soon.
Zelaya was overthrown in a military coup on June 28, but on Monday he returned from exile, sparking a tense standoff with the de facto civilian government that has promised to arrest him on charges of treason.
Brazil has said Zelaya can stay as long as necessary, but Micheletti told the South American heavyweight to either grant the deposed leftist political asylum or hand him over to Honduran authorities to be prosecuted.
"We urge the Brazilian government to define the status of Mr. Zelaya in a period of no more than 10 days," the government said in a statement. "If not, we will be obliged to take additional measures."
Carlos Lopez, the de facto government's foreign minister, said Brazil would lose its right to have an embassy in Honduras if it ignores the deadline. But he stressed that the government would respect the sovereignty of the compound and has no plans to storm the building to arrest Zelaya.
"There has been no discussion of raiding Brazil's compound," Lopez said at a news conference in Tegucigalpa where he faulted Brazil for escalating the crisis by agreeing to house Zelaya in its embassy.
"The Lula government is to blame," he added.
Since Monday, hundreds of soldiers and riot police have surrounded the embassy where protesters have mounted almost daily marches to demand Zelaya be reinstated.
"If they enter by force, they will be committing an act that contravenes all international norms," Lula said of the security forces outside the building.
ZELAYA URGES "FINAL OFFENSIVE"
Zelaya, a logging magnate who is rarely without his trademark cowboy hat, urged his followers to descend on the capital to pressure for his return.