Donald Trump has denied any involvement over increased US military spending at Prestwick Airport and visits to his Turnberry resort.

The US President said it had "nothing to do with me" following reports that the US Air Force has ordered a review into how it chooses accommodation for international trips after it emerged crew members had stayed at Trump Turnberry in Ayrshire.

Trump stated: "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).

"Nothing to do with me."

The United States Congress has launched a probe into whether increasing expenditure at the airport and allegations of cut-price deals at President Trump's golf resort offered to visiting US military personnel is a violation of the American constitution.

Elijah Cummings, chairman of the Congress oversight committee, wrote to then-acting secretary of defence Patrick Shanahan to raise "serious conflict of interest concerns" about Mr Trump making money from military trips to Scotland.

The letter from June reveals concerns US military spending at Prestwick - the closest airport to Mr Trump's resort - appears to have "increased substantially since the election".

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.

The committee is demanding to see all the financial documents from the US Department of Defence relating to Trump Turnberry, in addition to details of all communications between the two sides.

In addition to denying any knowledge of the Turnberry controversy, the US President also said he "had nothing to do" with the vice-president's decision to stay overnight at a Trump-owned resort in Ireland.

He stated that Mike Pence's "family has lived in Doonbeg for many years, and he thought that during his very busy European visit, he would stop and see his family".

Air force chiefs have now "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.