Treasury Department investigators are looking into an Aug. 15 $25,000 flight from New York to Washington that Secretary Steven Mnuchin took in a government jet, ABC News reported.
Mnuchin's flight aboard an Air Force C-37 jet followed a meeting in Trump Tower, and took less than an hour, ABC News reported. Transportation Secretary Elaine Chao also was aboard.
The pair appeared with President Donald Trump in a controversial news conference in which he defended his belief that both sides were responsible for racially charged violence in Charlottesville, Virginia.
Defense Department officials told ABC News records show Mnuchin's office had asked to use the jet, and Chao was added to the request.
According to ABC News, the Treasury Department's review was triggered after questions were raised about a military jet he and his wife, Louise Linton, used to go to Louisville and Fort Knox, Kentucky.
"We welcome the [Office of the Inspector General's] review and are ensuring the office has everything needed for a full evaluation of our travel procedures," the Treasury Department said in a statement, ABC News reported.
Mnuchin is not the only member of Trump's Cabinet whose travel has come under scrutiny.
Health and Human Services Secretary Tom Price is now under investigation by his department's inspector general for chartering dozens of private flights for domestic business trips that racked up about $300,000 in costs.