"I can confirm that we conducted a strike in Sadr City this morning. The targets were known criminal elements. Battle damage assessment is currently ongoing," a US military spokesman said.
Witnesses said the target of the air raid, in which US forces fired several missiles, was a small house adjacent to the al-Sadr hospital and used as a rest area by Shia pilgrims.
The impact of the attack damaged more than a dozen ambulances belonging to the hospital, one of the three main medical facilities in the district, and shattered the windows of the building.
Fighters killed
Elsewhere, US soldiers killed 14 suspected Shia fighters and an American soldier was killed in a roadside bomb attack in the latest clashes in Baghdad, the US military said on Saturday.
Another 100 people were wounded in clashes on Friday and Saturday in Sadr City, Iraqi health officials said.
The US military said 10 fighters were killed in clashes on Friday, including a sniper and a triggerman suspected of planting armour-piercing roadside bombs in Sadr City and the adjacent Ubaydi area.
US forces used aircraft and an Abrams battle tank in the attack.
The soldiers also killed four fighters early on Saturday elsewhere in Baghdad, the US military said.
Several vehicles and buildings were destroyed in the clashes, Iraqi police said.
Separately, the US military announced on Saturday that an American soldier died of wounds sustained the previous day in a roadside bomb that struck the soldier's vehicle during a combat patrol in eastern Baghdad.
The announcement comes a day after the military said another roadside bomb attack in eastern Baghdad killed a US soldier.