WASHINGTON (AFP) - Cuba has freed Alan Gross - a US contractor jailed on the communist-ruled island since 2009 - on humanitarian grounds at the request of the United States, a US official said on Wednesday.

US President Barack Obama and Cuba's President Raul Castro were both to speak at 1700 GMT on relations between the two countries, longtime Cold War-era adversaries, their respective governments said.

"This morning, Alan Gross has departed Cuba on a US government plane bound for the United States," the official said.

"Mr Gross was released on humanitarian grounds by the Cuban government at the request of the United States." Cuba arrested Gross, 65, in December 2009 for distributing communications equipment to members of the island's Jewish community while working as a contractor for the US Agency for International Development.

He was sentenced to 15 years in prison in 2011 after being convicted of "acts against the independence or territorial integrity of the Cuban state." His imprisonment was seen as a major obstacle to improving relations between Washington and Havana, which has taken steps to liberalise its Soviet-style economy.