Cuba has exchanged American citizen Alan Gross for three Cubans jailed in the United States. The prisoner swap is set to be the first step in a major overhaul of US-Cuba relations.

Cuban Jewish leaders say they have visited a U.S. government subcontractor imprisoned on the island. A statement from Beth Shalom Temple says they met with Alan Gross, of Maryland, on Thursday. The visit came two days after Gross marked four years in custody, and on the last day of Hanukkah.

On the fourth anniversary of his imprisonment in Cuba, former U.S. government contractor Alan Gross said he fears his country has “abandoned” him and appealed to President Obama to personally intervene in his case. In a letter to the president, sent via the U.S. diplomatic mission in Havana, Gross describes his isolation from the world, adding that his daughter and mother have been stricken by cancer, his wife has had to sell the family home in Maryland, and “my business and career have been destroyed.”