US forces launched two raids into Sadr City early on Saturday morning in one of the bloodiest exchanges in the Shi’ite slum since the American led invasion of 2003.
26 militants were killed in the shootouts with 17 others taken into custody.
The United States military say they targetted those suspected of having close ties to “Iranian terror networks.”
Sadr City is home to some two million people to the North East of the capital Bagdhad.
The American troops faced “significant” resistance coming under fire from rocket-propelled grenades but, there were no US casualties.
Residents say they saw American attack helicopters swoop over the city firing missiles into the densely-populated area.
Sadr City is home to Shi’ite cleric Moqtada al-Sadr a fervent anti-American.