Recently released dissidents Aide Gallardo, left, and Sonia Garro hold the Cuban national flag during a march in Havana on Jan. 11. As part of a normalization deal with the U.S., Cuba agreed to release 53 political prisoners. (Reuters)

All 53 political prisoners Cuba pledged to release as part of a normalization agreement with the United States have now been freed, the Obama administration said Monday.

“We welcome this very positive development and are pleased that the Cuban government followed through on this commitment,” said State Department spokeswoman Marie Harf.

“Clearly, we think this is a good thing,” she added.

The names of the 53 prisoners were part of a longer list the United States presented to Cuba during 18 months of secret talks that led to the announcement last month that the two governments would reestablish diplomatic ­relations. During the talks, the Cuban government responded by singling out the 53 detainees it was prepared to release.

Harf said the number of detainees who were left off the list refined by Cuba was “small” but declined to provide an exact count. Other U.S. officials said that the U.S. Interests Section in Havana had confirmed that the prisoners were actually released.

Dissident Wilberto Parada, 42, center, is reflected in a mirror with his son and wife in his home in Havana on Jan. 9, a day after his release. The island's government has freed all the dissidents it agreed to release, the U.S. said. (Ramon Espinosa/AP)

Neither the United States nor Cuba publicly disclosed the names of the 53, but copies of the list surfaced Monday after being provided to congressional leaders — an outcome the administration encouraged.

Many of those released are members of the Patriotic Union of Cuba, a small dissident group; other groups represented include the Ladies in White, made up of relatives of other detainees. A large number of those released had been charged or convicted of “assault,” a term frequently used for dissidents who resist arrest.

Most were held a relatively brief time, from several years to a few months, reflecting an apparent shift away from long-term imprisonments by the Cuban government to what Harf called “short-term detentions.” In recent years, Cuba has released many of the best-known long-term ­political prisoners.

Elizardo Sánchez, head of the Havana-based Cuban Human Rights and National Reconciliation Commission, said he could confirm that 40 prisoners on the list had been released since last month’s announcements; the others, he said, had been freed weeks and in some cases months earlier.

Sánchez said at least 70 individuals classified by his organization as political prisoners remain incarcerated. Some of them have spent up to 20 years in prison and a number are in poor health, he said.

The announcement came as Pope Francis, who was instrumental in forging the accord between the two countries to reestablish diplomatic relations, broke his official silence over the historic overtures that came after more than 50 years of Cold War-era estrangement.

Speaking to a group of diplomats at the Vatican, the pope said that “an example of how dialogue can build bridges is the recent decision of the United States and Cuba to end a reciprocal silence that lasted a half-century and draw near to each other for the good of their citizens.”

In a letter to senior lawmakers who were sent the list of 53 detainees, Secretary of State John F. Kerry noted that a small number had been released even before the Dec. 17 announcement and that “in the last few days, the remainder . . . were released.”

“We will continue to make clear to the Cuban government that neither those 53 individuals released, nor any Cuban exercising their universal right to have their voices heard, be subject to harassment, arrest or beatings,” Kerry wrote.

At a political event in Kentucky, the U.S. ambassador to the United Nations, Samantha Power, praised Cuba’s move as “heartening” to the families of the former prisoners, the Associated Press reported.

But she noted that it does not “solve the larger human rights problems” in Cuba — an issue that is certain to cast a shadow as the countries expand diplomatic dialogue.

The administration was hopeful that the prisoner release would be completed before the Jan. 21 beginning of talks in Havana over the process of reestablishing diplomatic relations, severed by the United States after the Cuban revolution brought the Communist government of Fidel Castro to power in 1959.

Critics of the agreement in this country, including some Cuban American citizens and lawmakers, had charged that Cuba was slow to comply with the pledge.

They said Havana got more than it had given in the accord, which included promises by President Obama to take executive action to ease restrictions on trade and travel.

The Treasury and Commerce departments plan to publish the new regulations as early as this week.

As a steady flow of releases began late last week, the State Department said that the names were “consistent with the cases that we raised with the Cuban Government.”

Meanwhile, a Venezuelan-based satellite television station featured a letter to Argentine soccer great Diego Maradona that it said was signed by Fidel Castro and dated Jan. 11. The station, which is partly sponsored by the Cuban government, broadcast a photograph of Maradona holding the letter, which the station said disproved widespread rumors late last week that Castro had died.

Castro, 88, who ceded power to his brother Raúl in 2008 after a prolonged illness, has not been seen in public for more than a year.