A South American union was born Friday as leaders of the region's 12 nations set out to create a continental parliament.
Some see the Union of South American Nations, or Unasur, as a regional version of the European Union. Summit host Brazil wants Unasur to help coordinate defense affairs across South America, and Venezuelan President Hugo Chavez calls it a counterweight to the United States.
Chavez said the U.S. is "trying to generate wars in South America" to "divide and conquer."
Brazil's president, Luiz Inacio Lula da Silva, invited other Latin American and Caribbean nations to join the venture.
"Unasur is born, open to all the region, born under the signs of diversity and pluralism," he said.
But leaders found their own reasons for division. Unasur's first secretary-general, Rodrigo Borja, resigned Thursday before the organization formally met. He complained that some leaders had balked at his vision of putting other regional trade blocs, including Mercosur and the Andean Community, under Unasur.
Leaders were also split over plans for a regional defense council that would resolve conflicts, promote military cooperation and possibly coordinate joint weapons production.
Colombia is the only nation that opposes joining such a council, saying "the terrorist threat" it faces at home, amid 40 years of civil conflict, precludes military cooperation. But, a government statement said, "Colombia does not oppose the creation of a working group to study the theme."
At the summit Friday, Lula urged wealthier nations to cut farm subsidies and import tariffs, and he defended biofuels, including ethanol, which critics blame for rising food prices.
"We should not be fooled one bit by the arguments of those who, for protectionist or geopolitical motives, feel uncomfortable with our industry, our agriculture and with the realization of our energy potential," Lula told the leaders.
Unasur could ease political tensions, promoting development on a continent where intra-regional trade in 2006 topped $72 billion, experts say.
South America's economy is expected to grow by 4.7% this year, according to the United Nations' Economic Commission on Latin America.