The German Parliament overwhelmingly voted Thursday to label the killings of Armenians by Ottoman Turks a century ago as genocide, prompting Turkey to recall its ambassador to Germany.
The motion, which was put forward by Chancellor Angela Merkel's governing coalition of right and left and the opposition Greens, passed with support from all the parties in Parliament. In a show of hands, there was one abstention and one vote against.
The vote heightened tensions between Germany and Turkey at a time when Ankara is playing a key role in stemming the flow of migrants to Europe.
Turkish President Recep Tayyip Erdogan said that "this decision will seriously impact Turkish-German relations."
Speaking during a visit to Kenya, Erdogan said recalling the ambassador for consultations was a "first step" and that the Turkish government would consider further steps to be taken in response to the vote.
Turkish Prime Minister Binali Yildirim called the German decision a "historic error." Yildirim said that Turkish people take pride in in their past and that "there is no event in our past that would cause us to bow down our heads in embarrassment."
Armenia's foreign minister welcomed the vote.
Historians estimate that up to 1.5 million Armenians were killed by Ottoman Turks around the time of World War I, an event viewed by many scholars as the 20th century's first genocide.
Turkey denies that the killings that started in 1915 were genocide and contends the dead were victims of civil war and unrest. Ankara also insists the death toll has been inflated.
Merkel was not present for Thursday's vote, with officials citing scheduling reasons. Her foreign minister, who like Merkel backed the motion, was on a trip to Latin America.
Opening Thursday's debate, Parliament speaker Norbert Lammert acknowledged that addressing historical events can be painful.
"But we have also seen that an honest and self-critical appraisal of the past does not endanger relations with other countries," he said. "In fact, it is a precondition for understanding, reconciliation and cooperation."
He said Turkey's current government is not responsible for what happened 100 years ago, "but it shares responsibility for what happens with it in the future."