WASHINGTON (AP) — The Energy Department says Energy Secretary Rick Perry has taken at least six trips on government or private planes costing an estimated $56,000.

The report comes as top officials in the Trump administration undergo scrutiny for their use of costly private or military air travel at taxpayers’ expense.

Three of Perry’s trips were on government planes, including one on an Energy Department plane to the Hanford nuclear site in Washington state, and two military flights to national labs in Idaho and New Mexico.

Perry also flew on private planes to visit a Pennsylvania coal plant and nuclear sites in Ohio and Kansas City.

Perry’s office released details about the flights to the House Oversight Committee, which is investigating non-commercial travel by the Trump administration.