Senator Robert Menendez, the top Democrat on the Senate Foreign Relations Committee, had used his powers to block sales of tens of thousands of precision-guided bombs to Saudi Arabia and the United Arab Emirates, fearing they would contribute to the humanitarian crisis in Yemen, where the US allies are mounting an offensive.

But the administration informed lawmakers that it was going around a legally required review by Congress to approve the sales as part of a total of 22 arms transactions to Saudi Arabia, the United Arab Emirates and other nations, Menendez's office said.

"I am disappointed, but not surprised, that the Trump administration has failed once again to prioritize our long-term national security interests or stand up for human rights, and instead is granting favors to authoritarian countries like Saudi Arabia," Menendez said in a statement.

He said that the administration, in explaining its intervention, "described years of malign Iranian behavior." But Menendez said the administration failed to meet the legal definition of an emergency and he vowed to work with lawmakers to counter the decision.

"The lives of millions of people depend on it," Menendez said.

The State Department, which handles foreign arms sales, did not respond to requests for comment.

The sales come after Trump vetoed a move by Congress to stop US support for the Saudi-led war in Yemen, where tens of thousands have died and millions risk starvation in what the United Nations calls the world's biggest humanitarian crisis.

Secretary of State Mike Pompeo has resolutely defended the US support for the Saudis, noting that the Huthi rebels who control much of Yemen are allied with US adversary Iran and saying that Huthi rocket attacks into Saudi Arabia could kill Americans taking commercial flights.

Also on Friday, Trump said he was deploying 1,500 additional US troops to the region to counter Iran, part of a major US pressure campaign to roll back Tehran's influence in the Middle East.

- Outrage at Saudis -

Outrage at Saudi Arabia has grown in Congress, even among some of Trump's Republican allies, after the October killing of Jamal Khashoggi, a Virginia resident who had written critically of Saudi Crown Prince Mohammed bin Salman in The Washington Post.

Khashoggi was strangled to death and his body dismembered after he visited the Saudi consulate in Istanbul to complete paperwork for his wedding, according to US and Turkish officials.

"Rather than stand up against those who murdered Jamal Khashoggi and are working against US interests, the Trump administration decided to do an end run around the Congress and possibly the law," Menendez said.

Trump, in a lengthy statement after Khashoggi's death, said he was not concerned over whether Prince Mohammed ordered the killing as Saudi Arabia was a major buyer of US weapons.

But Menendez said that the administration was putting arms sales at risk by bypassing Congress.

"With this move, the president is destroying the productive and decades-long working relationship on arms sales between the Congress and the executive branch," he said.