Baghdad ? A rocket slammed into Baghdad’s city hall and another hit a downtown park Tuesday as more frightened civilians fled a Shiite militia stronghold where U.S.-led forces are locked in fierce street battles.

The American push in the Sadr City district – launched after an Iraqi government crackdown on armed Shiite groups began in late March – is trying to weaken the militia grip in a key corner of Baghdad and disrupt rocket and mortar strikes on the U.S.-protected Green Zone.

But fresh salvos of rockets from militants arced over the city, wounding at least 16 people and drawing U.S. retaliation that escalated civilian panic and flight to safer areas.

One rocket – apparently aimed at the Green Zone – blasted the nearby city hall. Three 122 mm rockets hit parts of central Baghdad, including destroying some playground equipment in a park. An Iraqi police station was damaged by a rocket that failed to detonate, the U.S. military said.