(CNN) More than 60 lawmakers in the House are fighting to delay the Obama administration's planned sale of $1.15 billion in arms and military equipment to Saudi Arabia, citing the growing number of civilian casualties in Yemen caused by the Saudi-led military coalition.
In a longshot bid to stall the sale, the bipartisan group of 64 House members, led by California Rep. Ted Lieu, has called on the White House to withdraw the request for congressional approval for the sale until Congress can fully debate American military support for the Saudis. Among the lawmakers who signed the letter, which was sent to President Barack Obama, are several members of the House Armed Services Committee and House Committee on Foreign Affairs.
"This military campaign has had a deeply troubling impact on civilians," the lawmakers wrote in the letter, which was first reported by Foreign Policy. "According to the UN Office of the High Commissioner for Human Rights, 3,704 civilians, including 1,121 children have been killed during the conflict. 2.8 million Yemenis have been internally displaced by the fighting, with 83 percent of the population now dependent on humanitarian assistance for survival."
The United States has backed a Saudi-led coalition of Arab countries in an 18-month campaign against Shiite Houthi rebels and their allies in Yemen. UN-led peace talks to end the conflict broke down last month, and airstrikes resumed.
The Doctors Without Borders group is pulling out of a half-dozen medical facilities in northern Yemen due to what the humanitarian organization described as "indiscriminate bombings and unreliable reassurances" from the Saudi-led coalition, after an attack last month hit one of its hospitals, killing 19 and wounding 24.
Saudi Arabia was the top recipient of American-made arms from 2011 to 2015, according to the Stockholm International Peace Research Institute.
Congress has 30 days to consider the sale, which was approved by the State Department on August 9, and the deadline is soon to pass, meaning lawmakers would not be able to delay the sale. The letter indicated that the lawmakers were frustrated that the clock began ticking in the middle of the seven-week summer recess, which just ended Tuesday.
"Any decision to sell more arms to Saudi Arabia should be given adequate time for full deliberation by Congress," the letter said. "We are concerned, however, that the timing of this notification during the August congressional recess could be interpreted to mean that Congress has little time to consider the arms deal when it returns from recess within the 30 day window established by law."
The most recent congressional effort to thwart the sale of armaments to Saudi Arabia came from Connecticut Sen. Chris Murphy, who unsuccessfully pushed a resolution earlier this year that would make air-to-ground weapons and ammunition sales to Saudi Arabia subject to a certification process.
"There's an American imprint on every civilian life lost in Yemen," Murphy told CNN's Jake Tapper last month. "Why? It's because, though the Saudis are actually dropping the bombs from their planes, they couldn't do it without the United States."
State Department spokesman John Kirby told CNN that the US shares some of the lawmakers' concerns.
"We have had some concerns with the conduct of some coalition operations in Yemen, and we've not been bashful about expressing those privately or publicly," Kirby said Friday. "I can assure you that (Secretary of State John Kerry) raised those concerns with Saudi leaders when we were in Jeddah."
Kerry traveled to Saudi Arabia last month and met with Saudi King Salman. Kerry recently announced nearly $189 million in additional humanitarian aid for Yemen, bringing the total to more than $327 million since October 2015.