Oct. 27 (UPI) — Authorities in Britain on Tuesday charged a 24-year-old man with spying for a foreign intelligence service, allegedly Iran, in relation to an incident at RAF Fairford in September in which a group of masked men in vans were arrested by counter-terrorism police near the base in the middle of the night.

The Crown Prosecution Service said in a news release that Mohmed Ahmad Abdulkarim of London was charged under the National Security Act with assisting a foreign intelligence service by carrying out activities in Britain between Aug. 31 and Sept. 28 “likely to materially assist a foreign intelligence service.”

“In this case, we believe that country to be Iran,” said Head of National Counter Terrorism Policing, Assistant Commissioner Laurence Taylor.

A second man, Nouman Essghir, 24 and also from London, was charged with a single National Security offense that on Aug. 22 he entered, scoped out or got too close to a prohibited place “for a purpose prejudicial to the safety or interests of the United Kingdom.”

Both men are due to appear at Westminster Magistrates’ Court later on Tuesday.

Five others arrested on suspicion of explosives offenses during the alleged Sept. 27 incident in the Gloucestershire village of Whelford, a half mile from the base, and then re-arrested on suspicion of preparation of a terrorist act, are free on police bail, Counter Terrorism Policing said.

CTP added that an eighth man, a 25-year-old dual British-Iranian national who was re-arrested last week, has been released without charge but remains on strict police bail.

“We have seen a range of incidents in recent months that we believe have been directed by the Iranian state, and as the Director General of MI5 said just the other week, we are working together to intervene, identify and respond to that threat,” said CTP Assistant Commissioner Taylor.

RAF Fairford had been used by the U.S. military to fly missions amid its war with Iran.

A week after the security incident, the United States pulled out all of its bomber aircraft — at least a dozen long-range B-1s — stationed at the base, citing “threats.”