Pope Francis has quoted the word “genocide” in referring to the mass killings of Armenians 100 years ago, under Ottoman rule in World War I.

His phrase, which it is thought may anger Turkey, came as the Vatican held a mass attended by Armenia’s president and senior religious figures.

Ankara has consistently denied that the killings were genocide and strongly protested when the pope used the term two years ago.

“In the last century, our human family lived through three massive and unprecedented tragedies,” Pope Francis said. “The first, which is widely considered ‘the first genocide of the 20th century’, struck your own Armenian people.”

Armenia and many historians say up to one and a half million people were systematically killed by Ottoman forces in 1915.

Argentina, Belgium, Canada, France, Italy, Russia and Uruguay are among more than 20 countries which have formally recognised what happened to the Armenians as genocide.

The European Parliament and certain other internati