WASHINGTON (AP) — Cuba is releasing a U.S. spy imprisoned for nearly 20 years in the communist country, Obama administration officials said Wednesday, as part of the effort to restore diplomatic relations.

The spy is a non-American man whose identity remains secret, according to the officials, who spoke on condition of anonymity because they weren't authorized to discuss the matter publicly.

They said he was responsible for some of the most important counterintelligence prosecutions that the United States has pursed in recent decades, including a group known as the Cuban Five. The U.S. is releasing the group's three remaining prisoners in a swap for U.S. spy, they said.

The Cuban Five were part of the "Wasp Network" sent by then-Cuban President Fidel Castro to spy in South Florida. The men, who are hailed as heroes in Cuba, were convicted in 2001 in Miami on charges including conspiracy and failure to register as foreign agents in the U.S. Two were previously released after finishing their sentences.

The exchange comes as the two countries are starting talked to normalize full diplomatic relations. As part of the new policy, American Alan Gross also was released Wednesday from a Cuban prison. He was serving a 15-year sentence after being arrested in 2009 while working in the communist country to set up Internet access for the small Jewish community.

The U.S. officials said the unidentified U.S. spy provided information that led to the identification and conviction of Ana Belen Montes, a former senior analyst at the Defense Intelligence Agency. She was arrested in 2001 on charges of spying for Cuba and is serving a 25-year prison sentence.

He also helped with the prosecution of retired State Department intelligence analyst Walter Kendall Myers and his wife, Gwendolyn, who were convicted in 2010 of spying for Cuba for nearly 30 years and are serving life in prison without parole.

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