FILE - Turnberry, Scotland

The Trump Turnberry Luxury Golf & Hotel resort is seen in September 2017 in Turnberry, Ayrshire, Scotland.

Military officials are probing circumstances surrounding an overnight stay by the Maine Air National Guard at President Trump’s resort in southwest Scotland.

A spokesperson for the National Guard told Maine Public Radio that a unit of the air guard’s refueling wing stayed at the Turnberry resort in September 2018, while en route from a two-month deployment in Qatar. It appears they paid a per diem negotiated government rate.

Questions have arisen about the layover causing a potential conflict of interest, and whether Trump businesses are precluded from taking payment from members of the military.

The revelations come amid an investigation into how often Air Force service members have stayed at the Turnberry after stopping at the nearby Prestwick Airport, where fuel is available at standardized prices as part of a Department of Defense contract.

An Air Force spokesman told Politico, which first reported the Maine unit’s stay, that it appeared all procedures had been followed, but that a review of military stopovers at Trump organization properties was being conducted.

Additionally, a House Oversight Committee is examining the number of military stops at Prestwick and use of accommodations in the area, including a stop at the Turnberry by an Alaska Air National Guard unit in March.

President Trump, in a Tweet on Monday, said he knew nothing about the Prestwick landing or Turnberry overnight.

"I know nothing about an Air Force plane landing at an airport (which I do not own and have nothing to do with) near Turnberry Resort (which I do own) in Scotland, and filling up with fuel, with the crew staying overnight at Turnberry (they have good taste!)," the president wrote. "NOTHING TO DO WITH ME"

For several years, the Trump organization has used Prestwick Airport as a gateway to the Turnberry property, located about 30 miles away.

The spokesperson for the Maine National Guard told Maine Public Radio that the unit’s KC-135 plane landing at Prestwick was a location that had been approved by Air Mobility Command, and was part of an optimal route for flying back to Maine.