The US Air Force has reportedly ordered a review into how it chooses accommodation for international trips after it emerged that crew members had stayed at the Trump Turnberry resort.

It comes as US President Donald Trump is being investigated over a potential conflict of interest involving increased US military spending at Glasgow Prestwick Airport (bottom right) and visits to the luxury resort at nearby Turnberry in Ayrshire (below).

Air force chiefs have “directed Air Mobility Command to review all guidance pertaining to selection of airports and lodging accommodations during international travel”, according to a statement published by Politico.

Over the weekend it emerged that crew from a C-17 shared by the USAF and the Alaska Air National Guard stayed at Trump Turnberry when the aircraft stopped at Prestwick en route to Kuwait.

In the statement published by Politico, the USAF said: “While initial reviews indicate that aircrew transiting through Scotland adhered to all guidance and procedures, we understand that US Service members lodging at higher-end accommodations, even if within government rates, might be allowable but not advisable.

“Therefore, we are reviewing all associated guidance.

“Even when USAF aircrews follow all directives and guidance, we must still be considerate of perceptions of not being good stewards of taxpayer funds that might be created through the appearance of aircrew staying at such locations (review will include active duty, Guard Reserve).”

The USAF said its aircraft, primarily C-17s, have increasingly used Prestwick as a stopover location between 2015 and 2019 due to factors such as its 24-hour operations, its large parking area and its location on the route of flights to and from Europe and the Middle East.

US congress has launched a probe into whether increasing expenditure at the airport and allegations of cut-price deals at Mr Trump’s Ayrshire golf resort offered to visiting US military personnel is a violation of the American constitution.

Following reports of the airport offering “cut-price rooms for select passengers and crew” and free rounds of golf at Turnberry for US military staff and civilian air crews, Mr Trump has been warned his financial stake in the resort raises questions about the increase in airport spending.