Mr Lula said the international community "demands" Manuel Zelaya's reinstatement
Brazilian President Luiz Inacio Lula da Silva says the international community demands the reinstatement of ousted Honduran leader Manuel Zelaya.
Mr Lula told the UN that the crisis in Honduras is an example of where greater global political will is needed.
In another development, the UN has suspended any assistance for November's planned elections in Honduras.
A statement said Secretary General Ban Ki-moon did not not believe conditions are right for "credible elections".
The suspension is temporary, but a UN spokesperson gave no indication of when assistance might be resumed.
Mr Zelaya has been holed up in Brazil's embassy in Honduras since Monday with family members and about 40 supporters.
He had been in exile since July, when he was forced from the country at gunpoint, but made a surprise return to Honduras two days ago.
AT THE SCENE
Rodrigo Coelho, BBC Brasil, Tegucigalpa
There were seven military checkpoints from the El Salvador border to Tegucigalpa.
Troops were armed to the teeth. A soldier stopped our car and asked what we were carrying, who we were. As we approached mountainous Tegucigalpa, the road turned out to be more difficult than it looked.
The few people on the streets pointed out routes blocked by police and we had to take detours. As night fell, a group of teenagers played football by a blockade set up by civilians, paying no attention to the curfew. Totally Latin American.
The media is one of the few groups allowed to go around at night. I saw a ghost town, silence broken by gunshot. Hondurans I talked to were, above all, tired of what seems to them a personal dispute between two ambitious politicians.
"Put them in a boxing ring so they can sort it out themselves and we can get back to normal," people said.
Brazil has warned Honduran security forces not to enter the embassy in the capital, Tegucigalpa, and is seeking an urgent meeting of the UN Security Council to address the crisis.
"Without political will, we will see more coups such as the one that toppled Manuel Zelaya in Honduras," Mr Lula told the UN General Assembly in New York.
"The international community demands that Mr Zelaya immediately return to the presidency of his country and must be alert to ensure the inviolability of Brazil's diplomatic mission in the capital of Honduras."
Venezuelan President Hugo Chavez also called for international action, telling reporters: "The United Nations should demand that Zelaya be reinstated to government again," Reuters news agency reported.
In Honduras, troops have surrounded the embassy. Electricity, water and telephone services were cut off for a time on Tuesday before being partially restored.
Speaking to BBC Mundo on Wednesday, Mr Zelaya said forces surrounding the embassy were using "devices" that created "nervous problems" for those inside. He said "toxic gases" had also been thrown at the embassy.
He described the interim government as "an ambitious group, an economic elite that runs the whole economy of the country".
"The way out would be for the one who usurped power by force, illegitimately, to abandon power," he said.
The interim leader of Honduras, Roberto Micheletti, says he is willing to talk to Mr Zelaya.
But Mr Micheletti said Mr Zelaya must first accept that planned presidential elections would be held in November.
The government said on Wednesday that the political crisis has led to losses of millions of dollars.
TIMELINE: ZELAYA OUSTED
28 June: Zelaya forced out of country at gunpoint
5 July: A dramatic bid by Zelaya to return home by plane fails after the runway at Tegucigalpa airport is blocked
25-26 July: Zelaya briefly crosses into the country at the land border with Nicaragua on two consecutive days, in a symbolic move to demand he be allowed to return
21 Sept: Zelaya appears in the Brazilian embassy in Tegulcigalpa
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