United States President Barack Obama is allowing Americans to make unlimited transfers of money and visits to relatives in Cuba and easing other restrictions, ushering in a new era of openness towards the island nation ruled by communists for 50 years.

The formal announcement was made yesterday by presidential spokesman Robert Gibbs and, in Spanish, by Dan Restrepo, the president's top aide on Latin American policy.

"The president would like to see greater freedom for the Cuban people. There are actions that he can and has taken today to open up the flow of information to provide some important steps to help that," Gibbs said.

Gibbs said Obama was only one part of the equation, with the White House calling on Cuba to do more as well.

Political freedoms

With the changes, Obama aims to lessen Cubans' dependence on the regime of Fidel Castro, hoping that will lead them to demand progress on political freedoms, the spokesman said. About 1.5 million Americans have relatives on the island nation that turned to communist rule in 1959 when Castro seized control.

Some US lawmakers protested the changes, saying they could funnel money or goods to the Castro regime. Others, backed by business and farm groups seeing new opportunities in Cuba, wanted Obama to go farther and lift restrictions on travel by all Americans to Cuba.

Officials said Obama was keeping the decades-old US trade embargo, for now, at least, arguing that that policy pressures the regime to free all political prisoners as one step toward normalised relations with the US.

Restrepo said US policy towards Cuba "is not frozen in time". He had no timetable for when future decisions might be made.

Obama had promised to take these steps as a presidential candidate. It has been known for over a week that Obama would announce them ahead of his attendance this weekend at a Summit of the Americas in Trinidad and Tobago.