Cuba has released all 53 prisoners it had promised to free, senior U.S. officials said, a major step toward detente with Washington.

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.