Pope Francis has denounced the "genocide" of Armenians by Ottoman-era Turkish forces a century ago.
"Sadly that tragedy, that genocide, was the first of the deplorable series of catastrophes of the past century, made possible by twisted racial, ideological or religious aims that darkened the minds of the tormentors even to the point of planning the annihilation of entire peoples," he said as he arrived in Armenia on June 24.
"It's so sad how, in this case and in the other two, the great international powers looked the other way," Francis added, in apparent reference to the subsequent mass killings under Nazi Germany and the Soviet Union under dictator Josef Stalin.
Francis made the remarks on the first day of his three-day visit to the former Soviet nation, a trip aimed at further strengthening the Vatican's relations with Yerevan and the state-backed Armenian Apostolic Church.
In the run-up to the visit, the Vatican had refrained from using the term "genocide," mindful of Turkish opposition to the political and financial implications of the word given Armenian claims for reparations.
But on June 24, Francis declared unequivocally used the word to describe the mass killings
In April 2015, Francis held a mass at the Vatican's St. Peter's Basilica dedicated to the centenary of killings, calling them "the first genocide of the 20th century."
Turkey, which rejects the term genocide, had accused the pontiff of distorting history and recalled its ambassador to the Vatican in protest.
Francis was greeted at Yerevan's Zvartnots airport by President Serzh Sarkisian and Catholicos Garegin II, the head of the Armenian Apostolic Church.
Francis and Garegin then headed to the nearby town of Echmiadzin, which for centuries has been home to the Armenian church's headquarters. Armenia was the first nation to establish Christianity as a state religion, having done so in 301.
The two attended a religious ceremony in the town's cathedral.
Over the following days, Francis is set to pray at Armenia's main memorial to the 1915 killings, release two doves of peace near Armenia's closed border with Turkey, and pray for peace during an ecumenical prayer service with Garegin.
John Paul II became the first pope to visit Armenia with his 2001 trip and was the first pontiff to refer to the 1915 slaughter of an estimated 1.5 million Armenians in the Ottoman Empire as genocide, although he did so only in writing.