German president expected to label slaughter of Armenians as genocide at anniversary memorial

German President Joachim Gauck, third left, and his partner Dabiela Schadt, second left, attend an ecumenical service remembering the Armenian slaughter at the Berlin Cathedral Church in Berlin, Germany, Thursday, April 23, 2015. On Friday, April 24, Armenians will mark the centenary of what historians estimate to be the slaughter of up to 1.5 million Armenians by Ottoman Turks, an event widely viewed by scholars as genocide. Turkey, however, denies the deaths constituted genocide and says the death toll has been inflated. (AP Photo/Michael Sohn) (The Associated Press)

German President Joachim Gauck, left, attends the arrival of representatives of the Armenian Apostolic church, right, for an ecumenical service remembering the Armenian slaughter at the Berlin Cathedral Church in Berlin, Germany, Thursday, April 23, 2015. On Friday, April 24, Armenians will mark the centenary of what historians estimate to be the slaughter of up to 1.5 million Armenians by Ottoman Turks, an event widely viewed by scholars as genocide. Turkey, however, denies the deaths constituted genocide and says the death toll has been inflated. (AP Photo/Michael Sohn) (The Associated Press)

German President Joachim Gauck, second left, and his partner Dabiela Schadt, left, attend an ecumenical service remembering the Armenian slaughter at the Berlin Cathedral Church in Berlin, Germany, Thursday, April 23, 2015. On Friday, April 24, Armenians will mark the centenary of what historians estimate to be the slaughter of up to 1.5 million Armenians by Ottoman Turks, an event widely viewed by scholars as genocide. Turkey, however, denies the deaths constituted genocide and says the death toll has been inflated. (AP Photo/Michael Sohn) (The Associated Press)

Germany's president is widely expected to label the slaughter of Armenians by Ottoman Turks a century ago as genocide, underlining a shift in his country's stance after it previously avoided the term.

President Joachim Gauck will speak Thursday at a nondenominational service commemorating what the churches organizing it call genocide — a day before Germany's Parliament debates a motion that describes the killings as "exemplary" for the 20th century's history of expulsions and genocide.

The government has backed that formulation and said it was in contact with Gauck's office on his speech.

Turkey has lobbied fiercely to prevent countries from recognizing the massacres as genocide. It recalled its ambassador to the Vatican after Pope Francis used the term and its ambassador to Austria after lawmakers in Vienna did so.