Republicans on the Senate Armed Services Committee criticized Biden's reported sale of approximately $260 million worth of unused border wall materials, urging the immediate suspension of ongoing auctions in a letter to the secretary of Defense on Tuesday. 

"We are deeply disappointed to learn that rather than using construction materials that were purchased to secure the southwest border for that purpose, the Department of Defense has begun auctioning these materials off for other purposes," the letter stated. 

The letter was signed by every Republican member on the Armed Services Committee, including Sens. Eric Schmitt of Missouri, Tommy Tuberville of Alabama, Joni Ernst of Iowa, and Roger Wicker of Mississippi, the committee's ranking member.

Lawmakers also want the Department of Defense Inspector General to investigate Melissa Dalton, assistant secretary of defense for homeland defense and hemispheric affairs,  for what they say is her "failure to provide Congress accurate and timely information about the Department's plans regarding the use of these border wall construction materials."

FIRST REPUBLICAN PRIMARY DEBATE ON FOX NEWS SETS STAGE IN MILWAUKEE, WISCONSIN

President Joe Biden walks along a stretch of the U.S.-Mexico border

President Joe Biden walks along a stretch of the U.S.-Mexico border in El Paso, Texas, Jan. 8, 2023. (AP Photo/Andrew Harnik, File)

Multiple inquiries were sent to Dalton about the use of the border wall material from members and staff of the Senate Armed Services Committee, the letter stated. 

Lawmakers also stated they would not consent to a confirmation hearing for the nominee for undersecretary of defense for policy until their concerns are addressed. 

"President Biden’s attempt to subvert Congress and sell unused border wall materials is an abuse of taxpayer dollars," Ernst posted on X, formerly known as Twitter, on Tuesday. "I’m conducting critical oversight to halt his auctions."

By Sept. 5, lawmakers want the White House to give an account of how much the government originally paid for the materials, how much they were sold for, who bought them, and what they're being used for. 

GOP leaders also want to know how much money the department spent to keep the materials in storage, where they were stored, and who was paid for storing them.

"The FINISH IT Act requires the Department to use these construction materials to secure the southwest border as originally intended, or to transfer them to border states for that purpose," according to the letter. 

BIDEN QUIETLY AUCTIONS OFF BORDER WALL PARTS TO STUNT REPUBLICAN EFFORT TO RESTART CONSTRUCTION: REPORT

Immigrants clinging to the border

Immigrants wait for soup after crossing the border from Mexico on May 23, 2022, in San Luis, Arizona. (Mario Tama/Getty Images)

Introduced in May and led by Sens. Ted Cruz, R-Texas, Wicker, and Ernst, the FINISH Act proposes that the federal government utilizes border wall panels previously acquired but left unused.

It also proposes extending the U.S.-Mexico border wall using these panels or handing them over to states like Texas for their own border wall construction projects.

"During a border crisis, the White House should be working to enhance border security, not undermine it through such outrageous, behind-the-scenes maneuvering," Wicker said on X. "My FINISH It Act should be implemented without further delay."

BIDEN'S 'RIDICULOUS' PLAN TO SELL UNUSED BORDER WALL COSTS MONEY, LIVES AS DRUGS POUR IN: BORDER TOWN OFFICIAL

Border patrol truck at border fence

A Border Patrol agent walks between a gap along the border wall between the U.S. and Mexico in Yuma, Arizona, on June 1, 2022. (Patrick T. Fallon/AFP via Getty Images)

Reports of Biden quietly auctioning off border wall materials comes as the sale of "square structural tubes" was captured in a storage yard in Arizona. The tubes were made available for auction on GovPlanet, an online auction platform operated by the publicly traded Canadian company Ritchie Bros. Auctioneers, earlier this month.

CLICK HERE TO GET THE FOX NEWS APP

According to the New York Post, GovPlanet, which specializes in military surplus, has sold 81 lots of 28-foot-tall beams for about $2 million.

A U.S. Army Corps of Engineers spokesperson said in an email to Fox News Digital on Sunday that the "U.S. Army Corps of Engineers (USACE) is disposing of the excess border wall materials in accordance with the Federal Acquisition Regulation."

"USACE has already transferred approximately $154 million worth of the roughly $260 million of bollard panels and other materials in accordance with standard excess property disposition procedures. USACE stands ready to implement a decision regarding disposition of the remaining materials."

Fox News' Daniel Wallace contributed to this report.