Pope Francis has departed from his prepared speech, using the word "genocide" to describe the mass killings of Armenians in 1915, a description that infuriated Turkey when he used it a year ago.
In an address to Armenia's president and the diplomatic corps on Friday (local time), Francis used the Armenian term Metz Yeghern (the great evil), but then added to his prepared text "that genocide" to refer to what he also called "the first of the deplorable series of catastrophes of the past century".
There was no immediate reaction from Turkey, which last year promptly recalled its ambassador to the Vatican after the pope used the genocide term.
The envoy was kept away for 10 months.
Turkey accepts that many Christian Armenians living in the Ottoman Empire were killed in clashes with Ottoman forces during World War I, but it contests the figures and denies that the killings were systematically orchestrated and constitute a genocide.
It also says many Muslim Turks perished at that time.