Port of Spain  - UN Secretary-General Ban Ki-moon on Saturday praised improving ties between the United States and communist Cuba, which have been troubled for close to half a century.

"We have noted with interest the change of direction by the new US administration," Ban said at the Summit of the Americas in Trinidad and Tobago.

"It is a sign of changing times, of fresh winds blowing, in ways large and small," he said.

As head of the United Nations Ban said he welcomed "fresh approaches, new flexibility and a sense of give and take on all the inter-related challenges we face."

Cuba is the only country in the Americas that has no representation at the summit, since it was suspended from the Organization of American States (OAS) in 1962.

However, it has been the main topic of discussions. US President Barack Obama signalled Friday the opening of a "new beginning with Cuba," but cautioned that there was much ground to cover.

"I am prepared to have my administration engage with the Cuban government on a wide range of issues from human rights, free speech, and democratic reform to drugs, migration and economic issues," he said.

The issue of Cuba was not officially on the summit's agenda, but Latin America has been virtually unanimous in demanding the end of the decades-old US embargo on the communist island.

Earlier this week Obama announced an easing of travel and money restrictions for Cuban Americans. He acknowledged Friday that US policy on Cuba "has failed to advance liberty or opportunity for the Cuban people."

On Thursday, Cuban President Raul Castro said his government was willing to discuss any topic with Washington, including human rights, freedom of the press and the status of political prisoners. (dpa)