A Republican lawmaker blocked a resolution recognizing the Armenian genocide from being passed by unanimous consent in the Senate on Thursday — the third time a GOP senator has done so since the House passed the legislation by a 405-to-11 vote.

The senator, Kevin Cramer of North Dakota, was acting at the direction of the White House, said the resolution's Republican co-author, Ted Cruz.

"Those objections have been raised on behalf of the administration. The administration has asked senators to raise objections," the Texas senator said, calling that position "a mistake."

The resolution "acknowledges the horrific atrocity that was the Armenian genocide, the systematic slaughter of 1.5 million Armenians that for far too long has been covered up, has been hidden, and U.S. policy has not acknowledged," Cruz said.

Cruz's Democratic co-author on the resolution, Sen. Bob Menendez of New Jersey, said he was "deeply disappointed" by Cramer's objection — and noted that Cramer had co-sponsored similar legislation on the genocide in the past.

Cramer said on the Senate floor that "I support the spirit of the bill" but "I don't think this is the right time" to pass it because of the Trump administration's current negotiations with Turkey over a range of topics including Syria and missile defense.

"There's never a good time," Menendez said after Cramer's objection. "In my view there's always a right time, however, to recognize genocide as genocide."

The resolution, which was passed by the House in late October, recognizes the Ottoman Empire's mass killings of an estimated 1.5 million Armenians as genocide. That's accepted as fact by the vast majority of historians, but hotly contested by the Turkish government, which maintains the death toll is inflated.

The other Republicans who've objected to the bill are Sens. Lindsey Graham of South Carolina and David Perdue of Georgia. Graham launched his objection after meeting with President Donald Trump and Turkish President Tayyip Erdogan in the Oval Office.

Cramer issued his objection two days after he announced the Army Corps of Engineers had awarded a $270 million contract to a North Dakota company to work on the border wall. Cramer had repeatedly lobbied Trump to award the contract to the company, Fisher Sand and Gravel.

Cruz said he was optimistic the resolution would pass eventually.

"I think we're going to keep trying. Menendez and I are going to keep coming back. We'll come back again and we'll come back again and I'm hopeful we will get bipartisan agreement and pass this because it's the right thing," Cruz said. He said he wasn't concerned about Erdogan's threats that the measure's passage would harm U.S. Turkish relations. Cruz noted that 12 other NATO countries have acknowledged the genocide.

"I think Turkey is a NATO ally, and they're an important NATO ally, but that doesn't mean we have to ignore the truth and ignore reality," Cruz said.