Some Iraqi Army units are actually part of the Mahdi Army
September 4, 2007 7:58 am Shiite Militiamen in Iraqi Army and Police, Mahdi Army, IraqMany Trainees Are Complicit With Enemy Targets - washingtonpost.com, September 4, 2007
Building up the capabilities of the Iraqi security forces has been a pillar of Gen. David H. Petraeuss counterinsurgency strategy in Iraq, but the Iraqi army in Kadhimiyah is so thoroughly infiltrated with Mahdi Army militiamen that U.S. and Iraqi soldiers say it is close to useless. Iraqi soldiers in Kadhimiyah have been arrested and accused of attacking Americans and other Iraqi troops. Those who are not affiliated with the militia, which is loyal to the radical Shiite cleric Moqtada al-Sadr, tend to be too frightened for their families to pursue their corrupt colleagues.