UK spy chief says Iran is stepping up targeting of military bases

What happened: MI5 Director-General Ken McCallum said Iran is increasing attempts to target sensitive military sites, after suspicious vans near RAF Fairford and arrests at RAF Molesworth. Tehran denies involvement. Key numbers: Three suspicious vans near RAF Fairford on September 27. Five British men in their 20s arrested, released on bail. Two Latvian men arrested at RAF Molesworth. Why it matters: The US withdrew military jets from RAF Fairford over security concerns. McCallum said the Fairford incident is not unique, though he doubted Iran's ability to mount complex attacks in the UK. Coverage: 3 outlets in 24h

MI5 Director-General Ken McCallum said Iran is increasing attempts to target sensitive military sites, after suspicious vans near RAF Fairford and arrests at RAF Molesworth. Tehran denies involvement.

The US withdrew military jets from RAF Fairford over security concerns. McCallum said the Fairford incident is not unique, though he doubted Iran's ability to mount complex attacks in the UK.