A military spokesman has confirmed a US air strike on the Dora district of southern Baghdad on Friday, saying it had targeted men firing mortars into a neighbouring area.
Iraqi officials said that 13 civilians died in the air strike by US helicopters in the Al-Saha area of Dora.
Major Brad Leighton said: "Coalition forces surveillance elements observed a group of men setting up and firing mortars in... Dora.
"After they fired the mortars, the men hid the mortar tube nearby. Responding to this hostile action, coalition forces called for air support and engaged the men."
Amputated
Reuters television footage from Baghdad's Yarmouk Hospital showed three men and two boys who had been wounded in the attack, doctors had amputated the left leg of one of the boys.
A medic at the hospital said the dead included seven men, two women and four children.
The US military said it estimated two or three people were killed or wounded but could not give a precise figure as the bodies were removed before troops arrived at the scene.
Leighton said: "We regret when civilians are hurt or killed while coalition forces search to rid Iraq of terrorism. Terrorists continue to deliberately place innocent Iraqi women and children in danger by their actions and presence."
In a separate development, police said on Saturday that a mortar shell killed Abdul Khaliq Nasser, an Iraqi journalist in the northern city of Mosul, bringing to four the number of local media workers killed this month.
Nasser, who reported for a newspaper in the city, was killed outside his house in the western Bab al-Bayd area when the artillery round landed nearby late on Friday.