Luiz Inacio Lula da Silva, speaking first at this year's U.N. General Assembly, said developed countries must set more ambitious goals to cut greenhouse gas emissions and forge a pact by December to curb global warming. He also encouraged swift completion of the Doha trade round.

Lula has been in the spotlight this week at the United Nations, where he has played a lead role in an acute political crisis in Honduras, and he will be a powerful negotiator when the Group of 20 countries meet on Thursday in Pittsburgh to discuss ways to rebalance the global economy.

"A senseless way of thinking and acting, which dominated the world for decades, has proved itself bankrupt," Lula said of economic models that discourage regulation.

He blamed unfettered financial markets for causing the global crisis and said "it's not fair that the price of runaway speculation be paid by workers and by poor or developing countries."

Brazil says giving more voice to developing countries in the World Bank and International Monetary Fund would help fix the global economy and reflect the growing importance of emerging markets like China, India and Russia.

Lula also would like to see Brazil have a permanent seat on the U.N. Security Council.

This week, Brazil asked the Council to hold an urgent meeting on the crisis in Honduras, whose ousted leader is holed up in Brazil's embassy in Tegucigalpa.

BROKER IN HONDURAN CRISIS

Leftist Honduran President Manuel Zelaya was deposed in a coup in June. On Monday he returned to his country's capital and took shelter in Brazil's embassy to avoid arrest.

The embassy is now the scene of a tense standoff between Zelaya's supporters and security forces under the direction of the interim government that overthrew him.

Brazil's emergence as a key broker in the crisis has underscored what many see as waning U.S. influence in a Latin America that has tilted left this decade.

Lula, a former union organizer, shares political roots with left-wing presidents in Latin America, where Brazil has long viewed itself as the natural leader.

"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," he said.

(Editing by Alan Elsner)