Pope Francis attends his weekly audience in St. Peter’s Square on Dec. 17, 2014, at the Vatican. (Franco Origlia/Getty Images)

The Vatican was intimately involved in talks that resulted in the release Wednesday of American contractor Alan Gross and news that the United States and Cuba would begin working to normalize relations, with Pope Francis making a “personal plea” in a letter to President Obama and Cuban leader Raul Castro.

Talks between the two countries began last year, with Canada providing a place for representatives to meet. The Vatican also hosted talks — but in this case representatives from the Vatican attended, said senior U.S. administration officials during a news conference Wednesday.

Gross was released from Cuba in exchange for the United States releasing three Cubans jailed for espionage, according to the Associated Press.

The Vatican’s specific role wasn’t immediately clear, although one of the U.S. officials said that when the pope met with Obama earlier this year, the topic of Cuba received “as much attention as anything else they discussed.”

The president later Wednesday said he and Castro each received a letter with a “personal plea” from Francis to resolve the issues around the prisoners.

Theologian Miguel Diaz, who served as U.S. ambassador to the Vatican from 2009 to 2012, said the Vatican has been involved in talks from the start — along with many other parties — under Pope Benedict XVI and now under Francis.

“The voices that have been added to the choir asking for justice have been quite extensive. I don’t think at this point we need to focus on just one entity. There have been religious voices, there have been politicians, world leaders, humanitarian agencies, among others,” he said.

However, Diaz noted that the Latin American diplomatic firepower has increased significantly in recent years.

In addition to the Argentine pope, who took office in March 2013, Giovanni Angelo Becciu was brought from Cuba to Rome in 2011 to be a high-ranking member of the Vatican’s equivalent of the State Department. Becciu — who is Italian — was the Vatican’s representative in Cuba for two years before becoming the substitute for general affairs.

Francis also named Cardinal Pietro Parolin, who had been ambassador to Venezuela since 2009, as his secretary of state.

“You have two very astute and experienced diplomats [on the topic of Latin America] who are now part of the most intimate circles at the secretary of state,” Diaz said. “And of course now you have a pope from Latin America. When it comes to Latin American diplomacy nowadays, at the Vatican you have some very, very well-situated and experienced persons who know the realities.”

Carol Morello and Ed O’Keefe contributed to this report.

Here are the key moments from President Obama's speech about changes to relations with Cuba on Wednesday. (Sarah Parnass/The Washington Post)