Pope Francis, center, is greeted by the head of Armenia's Orthodox Church Karekin II, right, during an Armenian-Rite Mass in St. Peter's Basilica, at the Vatican, Sunday, April 12, 2015. Pope Francis on Sunday called the slaughter of Armenians by Ottoman Turks "the first genocide of the 20th century" and urged the international community to recognize it as such, sparking a diplomatic rift with Turkey. Turkey, which has long denied a genocide took place, immediately summoned the Vatican ambassador to complain and promised a fuller official response. (AP Photo/Gregorio Borgia), APTOPIX