Ankara immediately summoned the Vatican's envoy after the Pope made the comments at a service in Rome.
Turkey's Foreign Minister described it as "far from the historical reality".
Armenia and many historians say up to 1.5 million people were killed by Ottoman forces in 1915. Turkey has always disputed the number of dead.
The dispute has continued to sour relations between Armenia and Turkey. (+ BBC video) » | Sunday, April 12, 2015
