"I have a lot to learn and I very much look forward to listening and figuring out how we can work together more effectively," Obama said.
Obama said he was ready to accept Cuban President Raul Castro's proposal of talks on issues once off-limits for Cuba, including political prisoners held by the communist government.
While praising America's initial effort to thaw relations with Havana, the leaders pushed the U.S. to go further and lift the 47-year-old U.S. trade embargo against Cuba.
To Latin American nations reeling from a sudden plunge in exports, Obama promised a new hemispheric growth fund, an initiative to increase Caribbean security and a partnership to develop alternative energy sources and fight global warming.
As the first full day of meetings began on the two-island nation of Trinidad and Tobago Saturday, Obama exchanged handshakes and pats on the back with Venezuela's Hugo Chavez, who once likened Obama's predecessor, President George W. Bush, to the devil.
In front of photographers, Chavez gave Obama a copy of "The Open Veins of Latin America: Five Centuries of the Pillage of a Continent," a book by Eduardo Galeano that chronicles U.S. and European economic and political interference in the region.
When a reporter asked Obama what he thought of the book, the president replied: "I thought it was one of Chavez's books. I was going to give him one of mine." White House advisers said they didn't know if Obama would read it or not.
White House spokesman Robert Gibbs made a joke about it, noting the president doesn't speak or read Spanish: "I think it's in Spanish, so that might be a tad on the difficult side."
Later, during a group photo, Obama reached behind several leaders at the summit to shake Chavez' hand for the third time. Obama summoned a translator and the two smiled and spoke briefly.
Those two exchanges followed a brief grip-and-grin for cameras on Friday night when Obama greeted Chavez in Spanish.
"I think it was a good moment," Chavez said about their initial encounter. "I think President Obama is an intelligent man, compared to the previous U.S. president."
At a luncheon speech to fellow leaders, Chavez said the spirit of respect is encouraging and he proposed that Havana host the next summit.
"I'm not going to speak for Cuba. It's not up to me ... (but) all of us here are friends of Cuba, and we hope the United States will be, too," Chavez said.
The White House said Chavez was civil in his criticism of the U.S. during a summit meeting, but that there was no discussion of reinstating ambassadors who were kicked out of each other's countries last year. "Relationships depend on more than smiles and handshakes," Obama economic adviser Larry Summers told reporters later.
Bolivia President Evo Morales, a close ally of Chavez, said Obama's pledge of a new era of mutual respect toward Latin America rings hollow.
"Obama said three things: There are neither senior or junior partners. He said relations should be of mutual respect, and he spoke of change," Morales said. "In Bolivia ... one doesn't feel any change. The policy of conspiracy continues."
Morales expelled U.S. ambassador Philip Goldberg in September and kicked out the Drug Enforcement Administration the next month for allegedly conspiring with the political opposition to incite violence. Chavez expelled the U.S. ambassador in Venezuela in solidarity. The Bush administration subsequently suspended trade preferences to Bolivia that Bolivian business leaders say could cost 20,000 jobs.
But as the summit neared its close, Chavez said he soon expects to send an ambassador back to Washington. Obama administration officials didn't have an immediate comment on the announcement.
Obama also extended a hand to Nicaragua's Daniel Ortega, whom President Ronald Reagan spent years trying to drive from power. Ortega was ousted in 1990 elections that ended Nicaragua's civil war, but was returned to power by voters in 2006.
Ortega stepped up and introduced himself to Obama, U.S. officials said. But a short time later, Ortega delivered a blistering 50-minute speech that denounced capitalism and U.S. imperialism as the root of much hemispheric mischief. The address even recalled the 1961 Bay of Pigs invasion of Cuba, though Ortega said the new U.S. president could not be held to account for that.
"I'm grateful that President Ortega did not blame me for things that happened when I was three months old," Obama said, to laughter and applause from the other leaders.
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