British counter-terrorism police have arrested the seventh suspect in the investigation into the alleged plot at Fairford base

British counterterrorism police have arrested a 22-year-old British citizen suspected of preparing terrorist acts as part of an investigation into an alleged plot near Fairford air base. The arrest, announced on Tuesday, is the seventh in the case, and investigators are also examining the possibility of foreign state involvement.

The first five arrests took place on Sunday, 27 September, after police were alerted to three suspicious vehicles near the base used by the United States. No improvised explosive devices were found in the cars, but investigators discovered petrol. The suspects were detained on offenses related to explosives and the preparation of a terrorist act.

A 25-year-old British-Iranian citizen was subsequently arrested on Thursday on the same charge. All of the first six suspects have been released on bail, while the investigation continues with the support of the British intelligence service MI5.

Meanwhile, the Pentagon confirmed the withdrawal of all B-1 bombers from Fairford. President Donald Trump said the decision was made because the United States knew a threat existed. British Prime Minister Andy Burnham said the government believes Iran may have played a role in the incident.