The U.S. Air Force said Thursday it reviewed overnight stays by crew members who stopped at Glasgow Prestwick Airport between 2015 and 2019 to refuel and found about 6 percent stayed at President Trump’s Scottish golf resort.

The House Oversight Committee has been investigating an uptick in stays by the military at the five-star coastal Trump Turnberry hotel, which is about 30 miles from the airport, to determine whether the president has improperly directed crews to stay at his family-owned property.

“We reviewed the vast majority [of] the 659 overnight stays of Air Force crews in the vicinity at Glasgow Prestwick Airport between 2015 and 2019. Approximately six percent of those crews stayed at the Trump Turnberry,” said an Air Force spokesman in an emailed statement. “As a practice, we generally send aircrews to the closest, most suitable accommodations within the government hotel rate. The review also indicated that about 75 percent of the crews stayed in the immediate vicinity of the airfield and 18 percent stayed in Glasgow.”

A spokesman confirmed that Turnberry stays were within the Pentagon’s distance and cost limits.

Earlier this week, the Air Force launched a review of its selection of lodging accommodations at the Trump Turnberry resort in Scotland, acknowledging that it “might be allowable but not advisable.”

The stays result from two separate agreements that both predate Trump’s presidency. Before Trump ran for president, the airport agreed to send visiting crews to Trump’s course. And while President Barack Obama was still in office, the Air Force agreed to send refueling aircraft to the airport.

Now that Trump is president, those two arrangements mean that the Air Force has paid the commander in chief to rent rooms. The Oversight Committee is investigating, but so far no evidence has emerged showing that Trump has done anything to alter the existing arrangements.

Trump tweeted on Monday that the military crew stays at Turnberry have “NOTHING TO DO WITH ME.” Trump purchased the financially struggling resort in 2014 and has failed to turn a profit on his investment.

The Trump Organization said it charges the visiting aircrews about $100 each, and that — for about 90 percent of the year — its rates are too high for Defense Department reimbursement schedules.

Missy Ryan contributed to this story.