A woman prays at a church in Havana on Wednesday. Pope Francis will visit Cuba before flying on to the United States for his visit there in September, the Vatican said. (Enrique De La Osa/Reuters)

Pope Francis has added a stop in Cuba to his planned trip to the United States this September, a visit that will highlight his role as a peace-broker between the two countries and offer a boost to their efforts to mend relations after 50 years of rancor.

Francis will make a Cuba landing in late September before his previously scheduled stops in Philadelphia, New York and Washington, where he is expected to meet with President Obama and address Congress.

No further details of Francis’s Cuba plans were given by the Vatican on Wednesday. At a news conference in Brussels, where he has been meeting with European Union officials, Cuban Foreign Minister Bruno Rodríguez confirmed the pope’s visit. But there was no further statement from the Cuban government, and the island’s tightly controlled state media made no mention of the news until late Wednesday afternoon.

Whatever his plans, Francis will almost certainly be received warmly by a Cuban public that has shown a great deal of enthusiasm for papal visits in the past, if less so for the habit of disciplined church attendance.

With near-universal support among ordinary Cubans for reconciliation with the United States, Francis will give an important political boost to the only significant independent institution on the island — Cuba’s Catholic Church — and its role in nudging communist authorities toward broader reforms.

Francis’s stop in Cuba would be the third Vatican trip to the country since the Castro government ceased in 1992 to be officially atheist. In 1998, Pope John Paul II made a groundbreaking visit. In 2012 Pope Benedict XVI celebrated Mass before large outdoor audiences in Havana and Santiago de Cuba, the island’s second-largest city.

Benedict stated his opposition to the U.S. trade embargo during that trip. As his successor, Francis helped facilitate the secret conversations between Cuban officials and the Obama administration that culminated in the announcement in December that the two Cold War foes would reestablish diplomatic relations severed by Washington in 1962.

Granma, Cuba’s Communist Party newspaper, made no mention of the Vatican announcement Wednesday, but Orlando Márquez, a spokesman for the Havana Archdiocese, celebrated it as “great news.”

“It has been a special time in our country since the presidents of Cuba and the United States announced the process of ­re-establishing relations, and both of them thanked Pope Francis for his efforts to move the process forward,” he said in a statement. “That is well known in Cuba, and the Cuban people are grateful.”

Support from the Vatican has provided important political cover for the Obama administration, whose Cuba policy has been attacked by GOP opponents and Cuban American lawmakers, such as Sens. Marco Rubio (R-Fla.) and Robert Menendez (D-N.J.).

But Francis, who is Argentine, may have entered the Holy See with a more familiar knowledge of the degree to which many Latin Americans have viewed the U.S. policy toward Cuba as an anachronism and a drag on the United States’ image in the region.

Francis took an interest in bridging the U.S.-Cuba divide early on, reportedly sending letters to Obama and Raúl Castro that urged them to reconcile and offered to act as a go-between.

When Obama met privately with Francis in March, much of their hour-long encounter was devoted to the Cuba policy and Obama’s back-door diplomatic outreach to the Castro government. At one point, Obama aides and Cuban negotiators traveled to Rome to jointly brief Vatican officials on the state of their talks. They came away with the church’s blessing.

Ben Rhodes, one of the key White House advisers who made the Vatican trip and led 18 months of secret negotiations with Cuban officials, wrote Wednesday morning on Twitter: “President Obama is pleased that His Holiness Pope Francis will visit Cuba on his way to the US later this year.”

Relations between the two countries are slowly on the mend. Obama and Castro met April 11 for direct talks at the Summit of Americas in Panama, the highest-level encounter between the two countries since 1956. Diplomats from both sides have held several rounds of talks aimed at reopening embassies and reestablishing diplomatic relations.

But Cuba has balked at scheduling any flag-raising ceremonies while it remains on the U.S. blacklist of state sponsors of terrorism. Obama has recommended Havana’s removal, but the process probably will not be completed until late May at the earliest, and Cuban officials said they want to ensure an “appropriate context” for renewed ties.

Regardless of when that happens, Cuba will remain under extensive U.S. economic sanctions, which the Vatican and Obama oppose but only Congress has the authority to remove. Francis could address those sanctions in his September speech to U.S. lawmakers.

At the same time, the pontiff’s popularity in Cuba will give him a powerful platform to call upon Havana’s one-party state to ease its tight economic and political controls. Just as John Paul famously called upon Fidel Castro’s government to “open up to the world” in 1998, Francis will have an unparalleled chance to urge Cuban authorities to open up to democratic forces at home.

In a recent poll of 1,200 Cuban adults sponsored by Univision Noticias and Fusion Networks, eight in 10 respondents gave Francis a positive rating. Cuba’s Catholic Church was rated favorably by 70 percent of those surveyed, including non-Catholics.

Despite papal visits to the island in recent years, Cuba is not a heavily Catholic country such as Mexico or Brazil. Only 27 percent of Cubans said they were Catholic in the survey, while 44 percent said they had “no religion.” Masses on Sunday mornings are thinly attended in many Cuban neighborhoods.

But Cuba’s Catholic Church remains an important political institution. It helped negotiate the release of scores of jailed dissidents in 2011 and 2012.

The Castro government also has made major concessions to church authorities since the 1990s. Good Friday and Christmas are now official holidays on the island, and Midnight Mass is broadcast on Cuban state television every Dec. 24.

Read more:

How Pope Francis became such a force in foreign policy

The Philippines welcomes the pope

Obama removes Cuba from the list of state sponsors of terrorism