LONDON — British police said Tuesday they have rearrested two men on suspicion of assisting Iran’s intelligence service over the suspected plot at a U.S.-run air base in England last month.

Counter Terrorism Policing said the men, a 24-year-old British national and a 25-year-old dual U.K.-Iranian national, were arrested under the National Security Act.

The men were earlier arrested but had been bailed pending more investigation.

Police are investigating a suspected terror plot on Sept. 27 against the U.S.-run base at RAF Fairford in western England, which has been used to bomb Iran during this year’s war.

Scores of residents were evacuated from their homes near the base as armed police officers and army bomb-disposal experts swarmed the rural area. Police later said they had found a quantity of an accelerant — gasoline — in three vans at the site, but no explosives.

British authorities have linked Tehran to the incident, which led the U.S. to pull its bombers from RAF Fairford.

Five other men who were also arrested earlier remain on bail. No one has yet been charged.

Laurence Taylor, head of National Counter Terrorism Policing in the U.K., said detectives are looking at “many lines of enquiry involved in this hugely complex investigation.”

“This is very much a live investigation, and our evidence gathering continues, but at this time our position remains the same; we consider it highly likely that there is Iranian state involvement,” he said in a statement.

“Our investigators are continuing to examine what that level of involvement was and the ambition behind it,” he added.