Washington: Cuba has released American aid worker Alan Gross after five years in prison in a reported prisoner exchange with Havana that the United States said on Wednesday heralds an overhaul of U.S. policy toward Cuba.

A U.S. official said Gross was released on humanitarian grounds. CNN reported a prisoner exchange that also included Cuba releasing a U.S. intelligence source and the United States releasing three Cuban intelligence agents.

U.S. President Barack Obama was due to make a statement at noon (1700 GMT) on Cuba, the White House said, and U.S. official said Obama would announce a shift in Cuba policy. Cuban President Raul Castro was also set to make a statement at that time.

Cuba arrested Gross, now 65, on Dec. 3, 2009, and later convicted the U.S. Agency for International Development (USAID) subcontractor to 15 years in prison for importing banned technology and trying to establish clandestine Internet service for Cuban Jews.

The United States and Cuba have been locked in hostilities for more than half a century, and Obama is sure to face howls of protest in Washington and within the Cuban exile community in Miami for freeing the Cuban intelligence agents after 16 years in prison. Their freedom will be hailed as a resounding victory at home for Raul Castro.

The payoff for Obama was the release of Gross, whose lawyer and family have described him as mentally vanquished, gaunt, hobbling and missing five teeth.

Cuba arrested Gross in 2009 and later sentenced him to 15 years for attempting to establish clandestine Internet service for Cuban Jews under a program run by the U.S. Agency for International Development (USAID). His case raised alarms about USAID's practice of hiring private citizens to carry out secretive assignments in hostile places.

Cuba considers USAID another instrument of continual U.S.

harassment dating to the 1959 revolution that brought Fidel Castro to power. Fidel Castro retired in 2008, handing power to his brother Raul.

The United States has said it wants to promote democracy in communist-led Cuba, a one-party state that represses political opponents and controls the media. American officials accused Cuba of taking Gross hostage as a ploy to get their spies back.

The three Cuban intelligence agents, jailed since 1998, are Gerardo Hernandez, 49, Antonio Guerrero, 56, and Ramon Labañino, 51. Two others had been released before on completing their sentences - Rene Gonzalez, 58, and Fernando Gonzalez, 51.