Republicans and Democrats on Capitol Hill are urging President Trump not to go over Congress’s head to complete controversial arms sales to Saudi Arabia and other countries amid concerns that he may soon use his emergency powers to sidestep lawmakers’ power to check such deals.

Lawmakers and human rights advocates are anticipating that the administration may exploit a legal window that permits the president to circumvent congressional roadblocks, or “holds,” on proposed arms sales. Sen. Robert Menendez (D-N.J.), the ranking Democrat on the Senate Foreign Relations Committee, has placed such a hold on a planned sale of precision-guided munitions to Saudi Arabia, over concerns that the weapons may be used against civilian targets in war-torn Yemen.

Such holds are common, and Republicans and Democrats have placed them on arms sales to Saudi Arabia, the United Arab Emirates and other Persian Gulf countries in recent years. Presidents have seldom exploited their emergency powers to work around them — and the prospect that Trump may try to blow through several objections to such arms sales has alarmed lawmakers, who are anxious to protect their authority to have a say on the executive branch’s ability to export lethal weaponry to foreign actors.

On Oct. 2, 2018, Saudi agents killed Washington Post columnist Jamal Khashoggi inside the Saudi Consulate in Istanbul. What has been done in the aftermath? (Joyce Lee, Thomas LeGro, Dalton Bennett, John Parks/The Washington Post)

“The congressional review process exists so that the Senate can ask questions about whether a particular arms sale serves our national interests and supports our values, including human rights and civilian protections,” Menendez said in a statement Thursday, warning defense contractors that they, too, should be concerned that “the possible consequences of this will ultimately jeopardize the ability of the U.S. defense industry to export arms in a manner both expeditious and responsible.”

“In addition to suffering the reputational problems of delivering deadly weapons to governments that clearly misuse them, U.S. defense firms should exercise extreme caution that they are not opening themselves, their officers, and their employees to criminal and civil liability by exporting weapons pursuant to potentially invalid licenses,” Menendez said.

It is unclear how many Republicans oppose Trump’s rumored plans, but aides say key members of both parties are wary of losing an essential check on the executive branch’s power to influence global affairs through weapons sales.

The House and the Senate voted this year to end U.S. support for the Saudi-led coalition operating against Iranian-backed Houthi rebels in Yemen’s civil war, citing concerns that American involvement was worsening a humanitarian crisis that has been declared the world’s worst. More than 20 million Yemenis are at risk of starvation, and hundreds of thousands could be affected by a cholera epidemic in the impoverished country.

Trump vetoed the legislation, and lawmakers could not muster the numbers to overcome that veto. But even some Republicans who opposed the measure have cautioned the president against transferring nondefensive weapons to Saudi Arabia. That opposition gained bipartisan traction after intelligence officials informed lawmakers that the Saudi crown prince had ordered the killing in October of Saudi journalist Jamal Khashoggi, a Washington Post contributing columnist.

It is not yet entirely clear to lawmakers whether Trump is considering using his emergency powers to push through only the proposed arms sales to Saudi Arabia — contracts the president has frequently boasted about while exaggerating the expected revenue they would bring to the United States — or others as well. According to one Yemen advocate, the announcement could cover as many as 20 arms sales — and be justified by pointing to the recent escalation of U.S. tensions with Iran.

“Maybe Trump will say that ‘Iran’ is the emergency, but that’s a loophole that would allow any President to claim any number of Middle East crises as an ‘emergency’ and then Congress will never ever be able to object to an arms sale again,” Sen. Chris Murphy (D-Conn.) said Wednesday on Twitter , warning that Trump might exploit the “obscure loophole” in the Arms Export Control Act that gives him emergency authority.

“To state the obvious, there is no new emergency reason to sell bombs to Saudi Arabia to drop in Yemen,” Murphy wrote. “The Saudis been dropping the bombs on civilians, so if there is an emergency, it’s a humanitarian emergency caused by the bombs we sell the Saudis.”

This week, Secretary of State Mike Pompeo, acting defense secretary Patrick Shanahan, Chairman of the Joint Chiefs of Staff Joseph F. Dunford Jr. and a representative of the intelligence community briefed all House members and senators on the tensions with Iran, defending the administration’s recent moves to respond to what they said was clear evidence of an increased Iranian threat. Republicans largely endorsed their actions as prudent and a welcome change in the U.S. posture toward Tehran.

But Democrats emerged from those briefings accusing the Trump administration of spinning the intelligence to make the situation appear more dire and taking steps to goad Iran into taking any moderately provocative step that could justify U.S. military action. Democrats also expressed concern that the Trump administration would not consult Congress before taking such a step.