The 52 were among 75 dissidents arrested and sentenced to lengthy prison terms following a 2003 government crackdown.  Cuba has said it holds no political prisoners, only what it calls mercenaries who Havana claims are working with the United States to undermine Cuban communism.   

U.S. President Barack Obama has said he wants improved relations with Cuba, and his administration has eased travel and money transfer restrictions for Cuban-Americans with relatives on the island.  But Obama has said the embargo will stay in place until Havana takes steps toward democratic reform.

Tuesday, the State Department says diplomats at the U.S. Interests Section in Havana have met with families of remaining political prisoners in Cuba, following the recent release of some prisoners.

State Department spokesman P.J. Crowley said the meetings are part of an ongoing dialogue with families of Cuban political prisoners.  He said the U.S. is stressing in the talks that it hopes Cuba will release all the political prisoners.  But he said how far and how fast the Cuban government will go is a major question.

The United States and Cuba do not have formal diplomatic relations, but have interests sections that are technically part of the Swiss embassies in each other's capitals.