Andy Burnham, the Prime Minister, stated that "strong indications" point to Iran's involvement in events near RAF Fairford in Gloucestershire, where five men were arrested as part of a terror investigation.
Speaking to media at the Labour party conference in Liverpool, Burnham said he could not disclose further details pending the police investigation but confirmed Iran was believed to be involved.
Burnham also defended the decision to release the suspects on bail and expressed "complete confidence" in the security services.
The specific nature of the incident at RAF Fairford, a Royal Air Force base, was not detailed in the available information.