Treasury Secretary Steve Mnuchin formally requested to use a government plane for his honeymoon to Scotland, France and Italy earlier this summer.

Travel on such an aircraft could have reportedly cost American taxpayers $25,000 per hour to operate.

ABC News was the first media outlet to report Mnuchins request, which occurred last month. The request was so unusual it sparked an inquiry by the Treasury Departments Office of Inspector General.

A spokesperson for the Treasury Department said Mnuchins request was made to ensure that the secretary would have a secure line with which to communicate as a member of the National Security Council. Once the department found a different way to ensure secure communication, the request was withdrawn.

It is imperative that he have access to secure communications, and it is our practice to consider a wide range of options to ensure he has these capabilities during his travel, including the possible use of military aircraft, a Treasury spokesman said in a statement to The New York Times .

President Donald Trump defended Mnuchin on Thursday.

Ive known him for a long time, the president said after touring hurricane damage in Florida. Hes a very straight shooter.

The Treasury Departments inspector general is already looking into Mnuchins travel with his wife, actress Louise Linton, on an Air Force jet to Louisville and Fort Knox, Kentucky, last month that coincided with the solar eclipse. At their Fort Knox stop, they were close to where the eclipse occurred in totality.