Pope Francis plans to visit Armenia in June, the Vatican said on Friday, a trip that could upset Turkey if he again describes the century-old massacres of Christian Armenians as a genocide.

The Vatican spokesman said Francis would visit Armenia, for several days, most likely at the end of June, but the exact dates had not yet been set.

The pope triggered a row with Turkey almost a year ago when he said the killing of up to 1.5 million Armenians in World War One was "the first genocide of the 20th century", days before commemorations to mark the centennial of the massacres.

Muslim Turkey recalled its ambassador to the Vatican in protest and he stayed away for 10 months - a very long absence in diplomatic terms.

Turkey accepts that many Christian Armenians were killed in clashes with Ottoman soldiers when Armenians lived in the empire ruled from Istanbul, but denies hundreds of thousands were killed and that this amounted to genocide.

An overwhelming majority of Turks reject the accusation of genocide. The issue continues to thwart efforts to re-open diplomatic ties with neighboring Armenia, and their 300-km (190-mile) border has been closed for two decades.

Pope John Paul visited Armenia in 2001.