The US Senate has passed a resolution recognising the Ottoman Empire's killings of Armenians in the early 20th century as a genocide, a move that Donald Trump's administration has tried to block several times.

The resolution overwhelmingly passed the House of Representatives by a vote of 405-11 in October, but Republicans prevented a vote in the Senate at the insistence of the president.

Mr Trump attempted to halt the resolution ahead of a White House meeting with Turkish President Recep Tayyip Erdogan last month. South Carolina Senator Lindsey Graham said Mr Trump asked him to "object" to its passage.

Mr Graham said: "The only reason I did it is because he [Erdogan] was still in town. ... That would've been poor timing. I'm trying to salvage the relationship if possible."

After that White House meeting, Mr Erdogan told reporters that Congress had "cast a deep shadow" over relations between the two countries after its vote to define the massacre as a genocide.

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"If the US side really wants to act fairly", Mr Erdogan said, "it should refrain from taking a political stand on a matter that historians should decide."

North Dakota Republican Kevin Cramer also said the administration intervened in a vote following Mr Erdogan's visit.

Mr Cramer later told CNN he didn't know whether it could "be objected to much longer".

Fahrettin Altun, the Turkish presidency's communications director, wrote on Twitter that the "behaviour of some members of the US Congress is damaging the Turkish-American ties".

"History will note these resolutions as irresponsible and irrational actions by some members of the US Congress against Turkey," he wrote. "They will go down in history as the responsible party for causing a long lasting damage between two nations."

As many as 1.5 million Armenians were massacred between during the empire's decline.

"By passing my Armenian Genocide resolution, the Senate finally stood up to confirm history: What happened from 1915 to 1923 was — most assuredly — genocide," said New Jersey Democrat Bob Menendez, who sponsored the resolution. "There is no other word for it. There is no euphemism. There is no avoiding it. To overlook human suffering is not who we are as a people. It is not what we stand for as a nation. We are better than that, and our foreign policy should always reflect this."

Mr Erdogan appeared to clash with the White House at his Washington visit, during which he signalled that US-backed Kurdish fighters in northern Syria are among "terrorists" in the region, which Turkey invaded following the accelerated withdrawal of US troops paved the way for a Turkish invasion of Kurdish-controlled areas in the country.