The Islamic State in Iraq and Syria has a detailed structure that encompasses many functions and jurisdictions, according to ISIS documents seized by Iraqi forces and seen by American officials and Hashim Alhashimi, an Iraqi researcher. Many of its leaders are former officers from Saddam Hussein’s long-disbanded army who augmented their military training with terrorist techniques during years of fighting American troops.
Over the summer, the group pressed deeper into Syria, regaining some territory it had lost to other rebel groups and capturing several government military bases. It is still trying to consolidate its control along the border between Iraq and Syria.
ISIS fighters experienced some setbacks in Iraq, where American airstrikes helped Iraqi and Kurdish forces reclaim the Mosul Dam and the Turkmen city of Amerli.
Millions of dollars in oil revenue have made ISIS one of the wealthiest terror groups in history. Experts estimate the value of the output from the dozen or so oil fields and refineries under its control in Iraq and Syria at $1 million to $2 million a day.