As Iraq edges toward civil war, here's a look at major players and groups in the crisis.
Insurgents
The Islamic State of Iraq and the Levant (ISIL) is a Sunni jihadist group that has its roots in the al-Qaeda-linked insurgents that formed the backbone of the resistance against U.S. forces in Iraq after the 2003 invasion. It has since expanded operations into Syria, where it is fighting the regime of Bashar Assad, and has broken formal ties with al-Qaeda. It embraces a radical form of Islam and consists of battle-hardened fighters.