The US Senate has formally recognized the killings of Armenians a century ago as “genocide,” prompting angry denunciations by Turkey which rejects such a classification.
The Senate on Thursday unanimously passed the resolution. The nonbinding legislation had already passed the lower House of Representatives in October.
The resolution had been blocked three times at the request of President Donald Trump’s administration, but won approval on its fourth try.
The resolution comes at a time of mounting issues that have soured the relationship between the two NATO allies.
Some historians estimate that up to 1.5 million Armenians were killed around World War I.
Turkey accepts that many Armenians living in the Ottoman Empire were killed in clashes with Ottoman forces, but disputes the description, saying the toll has been inflated.
Ankara also argues that such accusations do not take into account the number of Turkish deaths during the conflict.
Armenian Prime Minister Nikol Pashinyan called the Senate move "a victory of justice and truth," but the government in Ankara condemned the move, warning it will impact US-Turkey ties.
Turkish Foreign Minister Mevlut Cavusoglu called the decision a “political show” while presidential spokesman Ibrahim Kalin said Ankara strongly condemned and rejected the measure.
“History will note these resolutions as irresponsible and irrational actions by some members of the US Congress against Turkey,” Fahrettin Altun, Turkey’s communications director, said on Twitter.
Trump has sought a closer relationship with Turkey and President Recep Tayyip Erdogan, but the US Congress has been united in its opposition to Turkey’s recent policy actions.
Republican senators have been angered with Turkey’s purchase of the S-400 missile system from Russia, which Washington says pose a threat to its F-35 fighter jets and cannot be integrated into NATO weapon systems.
The Republican lawmakers have also moved to punish Turkey over its incursion into Syria in October. They blame Trump for giving a green light to Ankara for its military offensive.