(AP) – The U.S. Air Force has withdrawn all its bombers from RAF Fairford, a military base in England used for operations against Iran, following an investigation into an alleged terrorist plot targeting the installation.

A Pentagon official confirmed Sunday that the aircraft had returned to their permanent bases in the United States. The official, who was not authorized to discuss sensitive military movements, spoke on condition of anonymity.

Military aviation monitoring groups, including the Military Air Tracking Alliance, had tracked B-52 and B-1 bombers operating from RAF Fairford since the start of the Iran war. Observers reported seeing numerous B-1s depart the base Sunday.

The withdrawal comes as President Donald Trump weighs whether to launch further strikes against Iran, despite earlier assurances that the military campaign would last only several weeks.

“We have decisions that I’ll make about Iran. Iran’s been decimated. So the only question is — it’ll either be the easy way, or the hard way,” Trump told reporters Saturday as he left the White House for a rally in Ohio.

The suspected plot has led to six arrests, with all those detained subsequently released on bail. Among them was a dual British-Iranian national arrested in central London last week on suspicion of involvement in a planned attack. The arrest followed a security incident at RAF Fairford in late September.

British authorities have suggested Tehran may have been connected to the incident, an allegation Iran denies. Tehran has previously warned that military bases used to launch attacks against Iranian territory could be considered legitimate targets.

Separately, British officials have accused Iran-linked networks of carrying out arson and other attacks in Britain and abroad, including incidents targeting Jewish communities. Authorities have warned that such activity could expand if tensions in the Middle East persist.

RAF Fairford, about 100 miles (160 kilometers) west of London, has served as a base for American bombers during several Middle East conflicts over the past decades.

The bomber withdrawal does not signal a broader U.S. military departure from the region. American forces continue to maintain a significant presence in the Middle East, with the USS Theodore Roosevelt aircraft carrier and the USS Malkin Island amphibious readiness group recently heading there, according to a U.S. official. The ships carry more than 7,000 sailors and about 2,000 Marines, and their arrival could bring the number of U.S. aircraft carriers in the region to three by the end of October.