WASHINGTON — The Defense Department's internal watchdog plans to review a recent Army Corps of Engineers decision to award a $400 million contract for border wall construction to a North Dakota company that has been publicly and privately endorsed by members of the Trump administration, including the president himself.

The review of the award to Fisher Sand & Gravel is an audit by the Pentagon's inspector general and comes in response to a request by Rep. Bennie Thompson of Mississippi, the Democratic chairman of the House Committee on Homeland Security. Thompson said the decision to award the contract should be reviewed because Fisher's "proposals reportedly did not meet the operational requirements of U.S. Customs and Border Protection" and because of "concerns about the possibility of inappropriate influence" on the Army Corps of Engineers.

"This is in response to your December 4, 2019, letter requesting that the Department of Defense Office of Inspector General conduct a review of the $400 million contract the U.S. Army Corps of Engineers awarded to Fisher Sand and Gravel Co. to design and build border infrastructure in Yuma County, Arizona," wrote Glenn Fine, the principal deputy inspector general, according to a copy of the inspector general's response to Thompson obtained by NBC News. “In your letter, you raised concerns about the possibility of inappropriate influence on USACE's contracting decision, and questioned whether the bid submitted by Fisher Sand and Gravel Co. met solicitation standards. You also questioned whether USACE made the award in accordance with federal procurement law and regulations."

"In response to your request, we have decided to initiate an audit of the solicitation and award of this contract," Fine wrote. "We are assessing the methodology of that audit and will formally announce the audit soon."

Thompson said Thursday he was pleased the inspector general "recognized the urgency of our request. ... The company had never been awarded a construction contract before and their wall prototype was late and over budget."

"Given the president's multiple endorsements of this company and the amount of taxpayer money at stake, I remain concerned about the possibility of inappropriate influence," Thompson said.

Download the NBC News app for breaking news and politics

For years and in recent meetings, the president has pushed the Army Corps of Engineers to consider awarding a contract for border wall construction to Fisher, according to three sources familiar with the discussions. And in a trip to the border in November, Trump's new acting secretary of homeland security and the chief of the Border Patrol's El Paso Sector toured a privately funded wall built by Fisher.

The renewed push for Fisher by Trump and DHS officials caught many by surprise, given the controversy in which the company has been entangled. The Washington Post first reported Sen. Kevin Cramer, R-N.D., held up the confirmation of a White House official in his demands to see border wall contracts that had gone out to other companies.

President Trump speaks during his visit to a section of the U.S.-Mexico border wall in Otay Mesa, Calif. on Sept. 18, 2019. Tom Brenner / Reuters

Officials feared Cramer was attempting to share proprietary information with Fisher so that they could make their bid more competitive. Cramer was a proponent of Fisher, a company from his home state, and had repeatedly made outreach on their behalf to the White House.

According to two U.S. officials, on a visit to the border early this year, Trump said he wanted the border wall to be two things: Cheap and good-looking. And Fisher had promised just that with its proposal of a concrete barrier for one-third of the cost of other bidders.

Fisher was officially awarded the contract Dec. 2. The details of its winning design are not known.

In a statement on Thursday, a Fisher spokesperson said, "Fisher is committed to full cooperation with any inquiry or audit. Fisher was one of 3 bidders on the Army Corps contract and Fisher was chosen for award based on the merits of its proposal as the Lowest Priced, Technically Acceptable offeror."

Border agents have repeatedly said they want the ability to see through any barrier built along the border, and the concrete design Fisher originally proposed would not give them that ability. There was also doubt that Fisher has the ability to carry through the project, especially at the low cost it has estimated.

In the spring of 2018, when Trump first began telling his advisers he wanted Fisher to be awarded a contract, officials at DHS pushed back, according to two sources familiar with the discussions.

"We had to explain the rules of federal procurement. You can't just pick a winner," said a person familiar with the conversations about Fisher with Trump in 2018. "He thought he could get three times the amount of wall because they were offering it for one-third of the price. But we were dubious."

Eventually, Trump was assuaged by Army Corps of Engineers officials who told him they would be sure Fisher was at least considered in the bidding process. Prior to the new contract, none of the contracts awarded for new or replacement wall had been given to Fisher. Recently, however, Fisher's name is back on the president's tongue and many of his allies, including his newly named acting DHS secretary.

Last month, Chad Wolf toured a 3.5-mile wall under construction by Fisher on private land near El Paso, Texas. The construction of the "water wall," which runs adjacent to the Rio Grande, was funded by crowd-sourcing through a group called "We Build the Wall."

Gloria Chavez, chief of the Border Patrol's El Paso Sector, said that after We Build the Wall began building its barrier, "Everything changed for us, and we were able to manage the border enforcement actions there even better."

We Build the Wall is led by former Trump adviser Steve Bannon and Kris Kobach, the former Kansas secretary of state whose views had been considered too extreme to head Trump's Department of Homeland Security. Trump's son-in-law and adviser Jared Kushner has also been a proponent of Fisher's and We Build the Wall in internal meetings, according to a former DHS official, a congressional aide and a U.S. official.