TEGUCIGALPA (Reuters) -- The de facto Honduran government insisted Thursday that it would not allow ousted President Manuel Zelaya to return to office, dampening hopes of a deal to end a political crisis after last month's coup.

Roberto Micheletti, named president by Congress after Zelaya was toppled in the June 28 coup, said he was open to dialogue to resolve the crisis but would not accept Zelaya back in power, as mediators are asking.
“I've clearly said it before and I say it again, if there is a solution where I have to step down I will do it willingly, but I cannot allow Zelaya to return as president,” Micheletti told reporters.
Rafael Pineda, who as minister of the presidency is No. 2 in the de facto government, told Reuters the administration was “firm, unchangeable” against Zelaya's return to power.
In neighboring Nicaragua, the exiled Zelaya asked a U.S. delegation to step up measures against the coup leaders and vowed to take his case to the International Criminal Court.
With mediator Costa Rica's efforts making little progress, Micheletti invited Enrique Iglesias, former Inter-American Development Bank head, to come to Honduras as a special envoy to try and rekindle negotiations.
The coup leaders are under pressure from Washington to reinstate Zelaya, and a source close to the de facto government said Micheletti might consider letting Zelaya back if there were assurances he would not try to derail democracy.
But Micheletti said Thursday that if Zelaya came back it would be to face trial.
“If he wants to retake control of the government, not under any circumstance,” Micheletti said.
Central America's most serious political crisis in nearly two decades has created a test for U.S. President Barack Obama as he tries to define his relationship with the region.
Obama has been pressured by Republican senators who want him to clarify his policy toward Honduras. Republican Senator Jim DeMint has threatened to delay a Senate vote on a nomination for a key State Department post for Latin America because of U.S. support for leftist Zelaya.
Washington has revoked diplomatic visas for four members of Micheletti's administration to pressure it to reverse the coup, which has been condemned by Latin American governments and the UN General Assembly. International loans and U.S. military aid have also been frozen.
Pineda said the de facto government would hold out until a November presidential election if talks do not produce a deal.
The de facto government's foreign minister Carlos Lopez echoed Pineda, saying the government was willing to endure tougher sanctions and hold out until November elections.
Zelaya upset the Supreme Court and many in Congress by trying to hold a referendum to change the constitution. Critics say he was trying to extend his mandate but he denies that.
His supporters have blocked roads in Honduras, a coffee and textiles exporter, but police have mainly kept their distance.
Thursday, soldiers and police in riot gear dispersed protesters in the capital with tear gas and shots, injuring several people. At least one had a serious bullet wound, a doctor at the capital's main hospital said.
Police said dozens were detained. A protest leader said they included a leftist candidate for November's election.