Pope Francis used the word 'genocide,' which is a term Turkish authorities have vehemently rejected. A highlight of the papal trip will include a visit to Armenia's main memorial to the 1915-17 killings.

"Sadly this tragedy, this genocide, was the first of the deplorable series of catastrophes of the past century," Francis said at the presidential palace in Yerevan on Friday.

Armenians have long sought international recognition for the killings as genocide, which they say left some 1.5 million of their people dead. As of 2016, the governments and parliaments of 29 countries, including Russia, Brazil, France, Germany, Italy and Canada, as well as 45 US states have recognized the events as a genocide.

Collective tragedy

Turkey has argued that it was a collective tragedy in which equal numbers of Turks and Armenians died. Turkey is the Ottoman Empire's successor state. Vatican officials had avoided using the term in the build-up to the visit and a copy of the pope's Friday speech distributed in advance did not contain the word.

It is the second time Pope Francis has made a public statement on the genocide. In April 2015, marking the centenary of the killings, he said the massacres were "widely considered the first genocide of the 20th century."

Watch video 01:06 Vatican spokesman: ‘Relations of the Holy See with Turkey are good’

The pope also highlighted the situation of Christians in the Middle East, with Armenia taking in many refugees. "Today Christians in particular, perhaps even more than at the time of the first martyrs, in some places experience discrimination and persecution for the mere fact of professing their faith," he said.

Pope Francis is the second pope to visit Armenia since it became an independent state following the collapse of the Soviet Union.

bik/jm (AFP, Reuters, dpa)