Maj. Gen. Mohammed al-Karawi died in the attack in Rutba in western Anbar province, Voice of America reported.
No group has yet claimed responsibility for the attack.
Violence in Iraq this year has been the worst since 2008, and spiked after security forces raided a Sunni protest camp north of Baghdad in April.
2014 amfAR Inspiration Gala [PHOTOS]
Sweden recognizes Palestinian state