British authorities arrested another man Tuesday in connection with a suspected terrorist plot targeting RAF Fairford, bringing the number of people detained over the security incident at the U.S.-run air base to seven.

A 22-year-old British national was arrested in Westminster, central London, on suspicion of preparing terrorist acts, according to Counter Terrorism Policing.

RAF Fairford, located about 100 miles west of London, has been used by U.S. military aircraft, including B-52 and B-1 bombers, during this year’s war with Iran.

Five British men in their 20s were initially arrested near the base’s perimeter in the early hours of Sept. 27. A 25-year-old British-Iranian man was later arrested in London. All six previously detained suspects have since been released on bail while remaining under investigation.

Police and military bomb-disposal teams descended on the area surrounding RAF Fairford after the initial arrests, prompting the evacuation of dozens of nearby residents. Investigators later found gasoline in three vans linked to the five men, but no explosives were discovered.

Vicki Evans, the senior national coordinator for counterterrorism policing, said investigators are continuing to examine the case from multiple angles.

British authorities have linked the incident to Iran, with Prime Minister Andy Burnham saying there were “strong indications” that Tehran played a role. Officials have not publicly disclosed the nature of the suspected plot or detailed the evidence behind the assessment.

Iran has denied involvement. Tehran has previously said that military bases used to attack Iranian territory could be considered legitimate targets.

The arrests came as the United States moved its B-52 and B-1 bombers away from RAF Fairford on Sunday. It remains unclear whether the aircraft movement was directly connected to the arrests or the security investigation.

President Donald Trump said Monday that the United States moved the bombers after receiving a threat, adding that he did not want to “tempt the enemy” by keeping them at the base.

British officials have declined to comment on reports that concerns about a possible drone attack prompted the bomber relocation, while the Prime Minister’s spokesman, Tom Wells, said RAF Fairford remained safe.

The investigation comes amid growing British concerns about hostile-state activity on U.K. soil. British security officials have previously warned about Iranian-linked proxies carrying out arson and other attacks, including incidents targeting Jewish communities.

Authorities have also said national security cases involving hostile states, including Iran, increased by 50% during the six months ending in December 2025.