U.S. President Barack Obama said Sunday he has seen positive signs from both Cuba and Venezuela, but "the test for all of us is not simply words but also deeds."

Venezuelan President Hugo Chavez, right, listens to U.S. President Barack Obama during the fifth Summit of the Americas in Port-of-Spain, Trinidad and Tobago, on Sunday. (Miraflores Press Office/Associated Press)

At a news conference closing the three-day Summit of the Americas in Trinidad and Tobago, Obama praised his country's recent exchanges with Cuba and Venezuela, saying there have been "potential positive signs in the nature of the relationship" between the United States and those countries.

"The test for all of us is not simply words, but also deeds," he added. "I do believe that the signals sent so far provide at least an opportunity for frank dialogue on a range of issues, including critical issues of democracy and human rights throughout the hemisphere."

At the summit, Obama shook hands with Venezuelan President Hugo Chavez and welcomed remarks made in Havana by Cuban President Raul Castro.

Last Monday, the U.S. administration lifted restrictions on Cuban-Americans who want to travel and send money to their island homeland. Obama said the nearly-50-year-old U.S. policy of isolating Cuba has "failed to advance liberty or opportunity for the Cuban people."

Within hours of the announcement, Raul Castro replied from a summit in Venezuela: "We have sent word to the U.S. government in private and in public that we are willing to discuss everything — human rights, freedom of the press, political prisoners, everything."

Trinidad and Tobago Prime Minister Patrick Manning, in closing remarks from Port-of-Spain, said he has never witnessed such a spirit of co-operation at an international conference.

"I am extremely pleased at what threatened to be a summit that could have been derailed by the agendas of individuals and individual countries has turned out to be a single example of co-operation and collaboration between the countries of the Western Hemisphere."

Brazilian President Luiz Inacio Lula da Silva, left, talks to Canadian Prime Minister Stephen Harper during the fifth Summit of the Americas in Port of Spain, Trinidad and Tobago, on Sunday. (Brennan Linsley/Associated Press)

Canadian Prime Minister Stephen Harper joined other leaders in declaring the summit an unexpected success.

"We all came here, I think, believing that we would have quite a battle among the radically different perspectives that do exist on certain subjects on hemispheric countries," he said. "That did not materialize. In fact, we saw the opposite. We saw the replacement of confrontation with dialogue."

Despite expressions of goodwill, the 34 leaders couldn't agree on a final declaration, instead adopting a much shorter final statement.

Chavez and allies including Nicaragua and Bolivia refused to sign chiefly because they want Cuba reinstated in the Organization of American States, which suspended it in 1962.

Harper said ideally, Cuba — excluded from the summit because it does not have a democratically elected leader — would be welcomed back into the fold, "but in such a way as to promote our own democratic and electoral standards."

Harper's main message at the summit was against protectionism and for more free trade in the region. He said promoting security and democracy were other key issues.

Spike in sales of book Chavez presented to Obama

While Chavez had been fierce critic of the United States under former president George W. Bush, he warmly greeted the current U.S. president on Saturday. However, he also let it be known Obama has much to learn about the region's history.

On Saturday, he handed Obama a Spanish-language version of the book Open Veins of Latin America: Five Centuries of the Pillage of a Continent, written by Eduardo Galeano. The book chronicles U.S. and European economic and political interference in Latin America.

The paperback edition was ranked 54,295 on the online retailer Amazon.com before the weekend. It had jumped to No. 5 by Sunday.

After meeting Obama, Chavez said he expects to send an ambassador back to Washington soon, ending a diplomatic impasse that began in September when the Venezuelan president expelled the U.S. envoy to Caracas.

As the summit was ending, Brazilian President Luiz Inacio Lula da Silva told reporters the "moment is right" for dialogue between Venezuela and the United States.

With files from The Associated Press