The U.S. Air Force has brought home its bombers stationed at a U.S.-run military air base in England used to strike Iran following an investigation into a planned terror attack at the RAF Fairford base.

The bombers were redeployed to their home bases in the United States, according to a Pentagon official who was not authorized to discuss sensitive military movements and spoke Sunday on condition of anonymity.

Aviation watchers such as the Military Air Tracking Alliance have observed dozens of B-52 and B-1 bombers operating out of RAF Fairford since the opening days of the Iran war. Observers noticed a host of B-1 bombers fly out of the base on Sunday.

The move comes as Donald Trump weighs options for his war on Iran — including new strikes — despite his initial promises to Americans that the campaign would last a matter of weeks.