WASHINGTON (AP) — 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 back 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.