All seven men arrested in the investigation, each in their 20s, now remain on police bail while "specialist teams continue to pursue all lines of enquiry," police said.
A 22-year-old man arrested in London earlier this week on suspicion of a terror offense has been released on bail, British counterterrorism police said. He is the seventh man arrested in connection with a security incident that British authorities have linked to Iran against RAF Fairford. American bombers had used this base to strike Iran during the ongoing war.
The man, a British national, was arrested Tuesday in the Westminster area of central London on suspicion of preparation of terrorist acts under Section 5 of the Terrorism Act 2006. He was released from custody under "strict bail conditions," police said.
All seven men arrested in the investigation, each in their 20s, now remain on police bail while "specialist teams continue to pursue all lines of enquiry," police said. Officers are appealing for anyone with information to come forward.
The decision to bail the first six men drew criticism last week from President Trump. He had said Iran "might be" involved in the incident, telling reporters on Sept. 28 that U.S. and British authorities worked "very closely" on the matter.
Scores of residents were evacuated from their homes near RAF Fairford, about 100 miles west of London, early on Sept. 27, as armed police and army bomb-disposal experts swooped on the rural area. Police later said they had found a quantity of an accelerant, gasoline, in three vans linked to the first five suspects, but no explosives.
Prime Minister Andy Burnham said the U.K. sees "strong indications" that Iran played a part in the incident, without saying why or what the nature of the suspected plot was.
Iran denied involvement in the incident but previously said it considers any base used to attack its territory a legitimate target. American bombers have used Fairford to strike Iran during the ongoing war.
The U.S. moved its B-52 and B-1 bombers from the base on Sunday, though it's unclear whether or how the move was connected to the arrests.
Mr. Trump told reporters Monday he didn't want to tempt "the enemy" by having the bombers there.
"We had a threat, and if we're going to be threatened, we would just move them, and that sort of alleviates that," he said, adding that those behind the unspecified threat "would be linked to Iran," without offering details.