WASHINGTON (Reuters) – Pope Francis and the Vatican played a key role in the reopening of U.S. diplomatic relations with Cuba and the release of imprisoned American Alan Gross, senior Obama administration officials said on Wednesday. The Vatican worked closely with both sides and hosted in-person meetings between Cuban and U.S. officials. Pope Francis, the first Latin-American pope, sent a letter to President Barack Obama and Cuban President Raul Castro urging them to resolve Gross’s case and pursue a closer relationship, officials said, speaking on condition of anonymity. …