Several ambulances were badly damaged, along with a number of civilian cars.
MORE CLASHES OVERNIGHT
The latest attack came after a night of more violence in Sadr City. The U.S. military said American and Iraqi forces killed 14 gunmen in battles overnight.
Hospital officials said 14 people had been killed and 25 wounded following the clashes. It was not immediately clear if the dead and wounded were gunmen or civilians.
The U.S. military has been carrying out air strikes on gunmen nearly every day in the militia bastion since fighting erupted more than a month ago.
It says militants have fired more than 700 rockets and mortars at various targets during that period, mostly at the Green Zone government and diplomatic compound.
The U.S. military blames rogue elements of Sadr's Mehdi Army militia for the rocket fire. It accuses Iran of arming, funding and training those militants, a charge Tehran denies.
A delegation from Iraq's ruling Shi'ite alliance was sent to Tehran this week to tell Iran to stop backing Shi'ite militias fighting security forces, members of the alliance have said.
The delegation returned to Baghdad on Saturday. In a brief statement on Iraq's al-Furat television, the head of the delegation, deputy parliamentary speaker Khalid al-Attiya, said Iran supported Baghdad in its fight against militants.
Attiya did not mention the U.S. accusations.
"The delegation saw a positive stance from the brothers in Iran to support the government's efforts in extending the sovereignty of the state and to fight the outlaws," Attiya said.
The U.S. military said this week that "very, very significant" amounts of Iranian weaponry had been found in the southern city of Basra and also Baghdad during an offensive against militiamen in those cities that began in late March.
U.S. military officials had planned to put on display some of the recently captured weapons but decided to let the Iraqis make their own case to Iran first.
Four U.S. Marines were killed by a roadside bomb in the western province of Anbar on Friday, the U.S. military said in a statement.
