WASHINGTON — The Pentagon’s internal watchdog will investigate military refueling missions in the Middle East and Africa after the U.S. undercharged allies by $331 million for its support in the Yemen civil war.

The Department of Defense Inspector General announced Tuesday it will audit the energy reimbursement process for the Defense Logistics Agency, which buys, stores and ships much of the U.S. military’s supplies.

The probe’s focus will be on U.S. Central Command and U.S. Africa Command, which were both involved in Yemen refueling missions. Auditors plan to visit Manama, Bahrain; Stuttgart, Germany, and Tampa, Florida, according a DoD IG memo to defense officials dated Jan. 28, 2019.

The U.S. announced in November, amid congressional outrage over the Oct. 2 death of Saudi writer Jamal Khashoggi, it would stop refueling Saudi aircraft fighting Houthi rebels in Yemen.

News of the DoD IG probe comes the day before U.S. lawmakers in both chambers act to push the Trump administration, yet again, to sever American involvement in Yemen’s civil war.

Sens. Bernie Sanders, I-Vt., Mike Lee, R-Utah, and Chris Murphy, D-Conn., as well as Reps. Ro Khanna, D-Calif., and Mark Pocan, D-Wis., announced plans Tuesday to reintroduce their resolutions invoking Congress’ war powers on Wednesday.

After years of officials telling lawmakers the U.S. was being completely reimbursed, the audit is “a day late and a dollar short,” Murphy said Tuesday.

“This administration has been playing fast and loose with the facts of our relationship with the Saudis for two years, so it’s not surprising they were not telling the truth about what this was costing taxpayers," he said.

The Pentagon acknowledged in December that “errors in accounting” led it to undercharge Saudi Arabia and the United Arab Emirates for U.S. aerial refueling of their aircraft in the Yemen civil war, and said it would bill Riyadh and Abu Dhabi for $36.8 million in fuel and $294.3 million in flight hours.

More broadly, lawmakers are seeking details of the arrangements between the U.S. and allies in the region, conducted through acquisition and cross-servicing agreements. ACSAs, as they’re known, are basically bilateral treaties through which the U.S. provides logistical support to allies.

Of the Pentagon’s 115 ACSAs, which cover a wide range of services and countries, 26 are through U.S. Africa Command, and 11 are through U.S. Central Command.

“Congress never authorized U.S. involvement in Yemen, but DoD still provided refueling services for Saudi airstrikes that cost thousands of lives – and then forgot to send the Saudis the whole bill," said Massachusetts Democratic Sen. Elizabeth Warren, a 2020 presidential hopeful and member of the Senate Armed Services Committee. "I’m glad the Inspector General will investigate. We need to hold the administration accountable for the operations it supports overseas and how our taxpayer dollars are being used.”

The DoD IG probe follows an inquiry from SASC’s ranking Democrat, Sen. Jack Reed, which prompted the Pentagon to acknowledge that U.S. Central Command had improperly tracked the costs for U.S. aerial refueling services in the Yemen civil war.

“We pointed out to them that a large sum of money was owed by the Saudis and the Emiratis, and there was an acknowledgement that’s the case,” Reed, of Rhode Island, said Tuesday. He said he expects the DoD IG to confirm that.

“It’s the law; that was the agreement they were operating under, and any other country would have to do the same thing,” Reed said. “It’s not being discriminatory toward them. We basically say: ‘We will fly you, and you will pay us.’ ”