Germany's parliament on Thursday recognized the Ottoman Empire's killing of ethnic Armenians and other Christians a century ago as genocide, prompting Turkey to recall its ambassador to Berlin and summon the German envoy to Ankara.
The Bundestag's almost-unanimous decision to term the World War I killings a genocide would "seriously affect the relations between Germany and Turkey," Turkish President Recep Tayyip Erdogan said while on a trip to Nairobi.
Successive Turkish governments have vehemently rejected the use of the term genocide to describe the mass expulsion and killings of as many as 1.5 million Armenians at the hands of the Ottoman Empire, of which Turkey is the successor state.
Chancellor Angela Merkel defended the parliament's decision, saying that disagreement on individual questions does not detract from her country's "amicable and strategic" relationship with Turkey.
Speaking at a joint press conference with NATO Secretary General Jens Stoltenberg in Berlin, Merkel said she wants to contribute to the promotion of dialogue between Turkey and Armenia.
Armenia - a former Soviet republic that has been fighting for recognition of the atrocities for years - welcomed the resolution. Foreign Minister Edward Nalbandian said the international community was still waiting for Turkey's own acknowledgement.
"While Germany and Austria, as former allies of the Ottoman Empire, are today acknowledging their part of responsibility in the Armenian genocide, the authorities of Turkey are continuing to obstinately reject the undeniable fact of genocide committed by the Ottoman Empire," Nalbandian said in a statement.
Turkey views the killings as part of a wider conflict during World War I, with casualties on both sides. The parliament vote triggered sharp responses from Turkish officials, often drawing on the Holocaust.
"You burn the Jews in the oven and then you get up to charge the Turkish people with genocide and slander them. Go look at your own history," Turkish Justice Minister Bekir Bozdag said, according to state-run Anadolu news agency.
Turkish Foreign Minister Mevlut Cavusoglu said this was not a way for Germany to deal with its own "dark history." The ministry pledged to take unspecified legal measures.
"This initiative of Germany constitutes an attempt to assimilate Turks and Germans of Turkish origin ... to alienate them from their own history and self-identity," the Foreign Ministry said in a statement.
"There is nothing in our history that makes us ashamed," Turkish Prime Minister Binali Yildirim said.
Burhan Kuzu, a top member of the ruling Justice and Development Party (AKP), echoed sentiments of nationalists, calling ethnic Turkish members of the German parliament who voted for the bill "traitors" and warning they "should not set foot" in Turkey.
Cem Ozdemir, a Green party lawmaker of Turkish descent and one of the main proponents of the resolution, said that the German Reich's complicity in the World War I killings meant that his country "has to acknowledge its share of the blame." Germany was an ally of the Ottoman Empire.
Norbert Lammert, the president of the Bundestag, said after an hour-long parliamentary debate that the resolution had been adopted with only one vote against it and one abstention.
"The current government in Turkey is not responsible for what happened 100 years ago, but it is partly responsible for what will happen in the future," Lammert said.
The vote was originally scheduled for last year, but was put on ice for fear of damaging German-Turkish relations.
The fact that Turkey is "doing great things" to support the European Union in managing the refugee crisis "does not change the facts - that unspeakable suffering was imposed on the Armenians," said Volker Kauder, the leader of Merkel's Christian Democrats in the Bundestag.
Merkel did not participate in the debate. Vice Chancellor Sigmar Gabriel was also absent, while Foreign Minister Frank-Walter Steinmeier was in Buenos Aires.