British police rearrested two men on suspicion of assisting Iran’s intelligence service in the suspected plot at a US-run air base in England, police said on Tuesday.

Counter Terrorism Policing said the men, a 24-year-old British national and a 25-year-old dual UK-Iranian national, were arrested under the National Security Act. Police are investigating a suspected terror plot on Sept. 27 against the US-run base at RAF Fairford in western England, which has been used to bomb Iran during this year’s war.