The release of the remaining prisoners sets a positive tone for historic talks next week aimed at normalizing relations after decades of hostility, the officials said.
They described the Cuban government’s release over the weekend of the last detainees on the list as a milestone but said they would keep pressing Havana to free more people the United States considers political prisoners.
The officials, speaking to Reuters on condition of anonymity, did not say how many prisoners were released over the weekend or identify them. But the White House will provide the names of all 53 to Congress and expects lawmakers to make them public, the officials added.
There had been questions over whether Havana would release all 53 prisoners as part of the deal Presidents Barack Obama and Raul Castro announced on Dec. 17 to restore diplomatic ties that Washington severed more than 50 years ago.
Intense secrecy surrounding the 53, whose names have been withheld by both countries, had fueled skepticism over Cuba’s intentions and played to critics who said Washington hasn't pressured Havana enough on human rights in exchange for normalizing ties and loosening economic and travel restrictions.
The U.S. exchanged three convicted Cuban spies for an agent who had spied for the U.S. government. The United States also received Alan Gross, a U.S. aid worker jailed in Cuba.
The Cuban government informed the Obama administration over the weekend that the last of those on the list of prisoners had been released, and the U.S. Interests Section in Havana, which handles consular affairs and other contacts for Washington, confirmed it, the officials said.
The U.S. officials said they would pressure communist-ruled Cuba to release more prisoners.
"The fact of the matter is there are other individuals whose cases we have raised in the past," one of the officials said. "We have every expectation of going forward in the future. We’re going to be wanting to raise the cases of different individuals who may be detained in Cuba for exercising their universal rights."
Cuba's government says there are no political prisoners on the island and typically describes dissidents as U.S.-paid mercenaries.