raul_castro_pope_francisPope Francis unexpected hero of US-Cuba relations breakthrough

Pope Francis has congratulated both the US and Cuba on restoring relations, as the Vatican together with Canada were confirmed to have played a significant role in the talks which broke 50 years of cold.

The Vatican said that it was a key player in negotiations between the two countries, "resulting in solutions acceptable to both parties." Pope Francis added that he will continue to be supportive of the process. It emerged on Wednesday that he had sent a personal letter to both US President Barack Obama and President of Cuba Raul Castro during the summer.

Earlier in the day, a US Senator had mentioned both Vatican involvement and the letter, saying that it had provided "greater impetus and momentum for us to move forward."

"Pope Francis sent letters to President Obama and to Cuban President Raul Castro this past summer urging a resolution of the matter of prisoners and progress in our bilateral relationship," US Ambassador to the Vatican, Kenneth Hackett, confirmed to Reuters.

Additionally, the Vatican was responsible for playing host to meetings between Cuban and US officials.

Canada was a host to the secret talks, it turned out Wednesday. Canadian Prime Minister Stephen Harper revealed his country's role in the negotiations and said that he stood behind a Cuba which acknowledged "the values of freedom, democracy, human rights and the rule of law."

Cuba exchanged American citizen Alan Gross for three Cubans jailed in the United States on Wednesday. The prisoner swap is set to pave the way for a major overhaul of bilateral ties, potentially bringing an end to over five decades of severed diplomatic relations.

Alan Gross, leaves following a press conference after being released by Cuba on December 17, 2014 in Washington,DC. (Reuters/Saul Loeb)

Alan Gross, leaves following a press conference after being released by Cuba on December 17, 2014 in Washington,DC. (Reuters/Saul Loeb)

US officials said Gross was transported on a government plane in the morning after being released on humanitarian grounds, which followed a request from the White House. He arrived at Andrews Air Force base near Washington DC. Footage broadcast by MSNBC showed him exciting the aircraft, where he was met by well-wishers.

The three Cubans had been part of the so-called 'Cuban Five.' The group was allegedly sent by former Cuban President Fidel Castro to carry out espionage in South Florida. The men, who were convicted by a court in Miami in 2001 on charges including conspiracy and failure to register as foreign agents, are widely lauded back home.

'Mutual interest for both nations' - Castro

On Wednesday, Castro spoke to his own nation of the change in diplomatic relations welcoming the improvements in the relations with the US. However, he added that some differences exist between the two e.g. over questions of sovereignty human rights. Castro still said that the countries must live with their differences "in a civilized manner".

READ MORE:Obama announces US will establish embassy in Cuba, lift sanctions

Castro reminded that the "economic, commercial, and financial blockade, which causes enormous human and economic damages to our country, must cease."

The United States severed diplomatic relations with Cuba over 50 years ago due to the Castro's socialist reforms and increased cooperation with the Soviet Union. Along with the severed ties, Washington also imposed a commercial, economic and financial embargo against Cuba in 1960. That embargo was soon expanded to include all imports to the small Caribbean island.

"I look forward to engaging Congress in an honest debate on lifting this embargo," President Barack Obama said.