As I recall, the Iranian militias assisted the Iraqi forces in taking back Fallujah. As far as I know, the Iraqi government still controls fallujah. I’m thinking that is ISIS’s next goal. Once Fallujah falls, they will be really close to Bagdad and all of the Anbar province will effectively be in ISIS’s hands.
Bagdad had been sacked and re-sacked dozens of times over many centuries by various factions of Islam.