About 1,200 auditors sharpened their pencils and pored over the Pentagon's accounting books and were able to identify discrepancies that will likely take years to resolve, Reuters reported.

The undertaking was massive and an early goal for the Trump administration.  These auditors looked into spending on military personnel and weapons systems, the report said.

Patrick Shanahan, the deputy secretary of defense, said "the fact that we did the audit is substantial," and said the agency "never expected to pass."

A Pentagon spokesman clarified that an audit is not a ‘pass-fail’ process and noted that it did not receive the lowest possible rating in any area. Reuters reported that Shanahan did not mention how much money was unaccounted for in the study.

"Some of the compliance issues are irritating to me," he said. "The point of the audit is to drive better discipline in our compliance with our management systems and procedures."

Rep. Barbara Lee, D-Calif., tweeted that the results are why the U.S. "must" audit the Pentagon.

"The unchecked waste, fraud and abuse at the Pentagon is an insult to the American people," she tweeted.

DefenseNews.com reported that the audit has been something that lawmakers have pushed for in the past.

Sen. Bob Corker, R-Tenn., in March, wondered aloud how the Defense Department can "turn entire countries into craters," but has avoided an audit. The report said Congress first legislated an audit requirement in 1990.

Reuters reported that the U.S. defense budget in 2018 was about $700 billion.

Shanahan said the Pentagon can improve on compliance with cybersecurity policies and inventory.

"If I’m a taxpayer, what I want to see is: 'You did the audit, you have all these findings. How long is it going to take for you to fix those?'" Shanahan told Defense News. "Then show me next year it takes less to audit and you have fewer findings."