Obama also sought out Venezuela's fiery leftist president, Hugo Chavez, for a quick grip and grin.

What did he say to a leader who once likened his predecessor to the devil?

"I said 'como estas'", Obama told reporters with a laugh.

In an opening speech to the 34-nation gathering, the president promised a new agenda for the Americas, as well as a new style.

"We have at times been disengaged, and at times we sought to dictate our terms," Obama said to loud applause. "But I pledge to you that we seek an equal partnership. There is no senior partner and junior partner in our relations."

That approach was on display Saturday in the first full day of the summit in the two-island nation of Trinidad and Tobago, just off Venezuela's coast.

Obama took part in a series of plenary sessions, group gatherings and one-on-one meetings that the White House scrambled to arrange. He hoped to make time for individual sessions with leaders from Canada, Colombia, Peru, Haiti and Chile, aides reported.

But Obama also extended a hand to a leader Ronald Reagan spent years trying to drive from power: Nicaragua's Daniel Ortega. The Sandinista president stepped up and introduced himself, U.S. officials reported.

Yet soon after, Ortega, who was ousted in 1990 elections that ended Nicaragua's civil war but who was returned to power by voters in 2006, 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.

But perhaps the biggest applause line was his call for a fresh start in relations between Washington and Havana.

"I know there's a longer journey that must be traveled to overcome decades of mistrust, but there are critical steps we can take toward a new day," he said.

On Tuesday, Obama ordered an easing of travel and remittance restrictions for Americans with relatives in Cuba. Within hours, Castro — who took over from his ailing brother Fidel a year ago — responded with an offer of talks on "everything" that divides the two countries.

The White House welcomed the offer, but suggested actions would be better, such as releasing some of Havana's scores of political prisoners.

Added Obama: "I am not interested in talking for the sake of talking. But I do believe that we can move U.S.-Cuban relations in a new direction."

Cuba became a dominant issue even though the summit was taking place amid the worst global downturn since the Great Depression.

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 new regional partnership to develop alternative energy sources and fight global warming.

But most of all, he offered an end to old hemispheric arguments.

"I didn't come here to debate the past," Obama said. "I came here to deal with the future ... We must learn from history. But we can't be trapped by it."