A bomb blast near a US patrol in Baghdad killed nine Iraqis and wounded 23 people on Thursday.
Iraqi police said some US troops were hit by the blast in the eastern Camp Sara district, where both Sunni and Shi'ite Arabs live.
US forces said they killed 16 more fighters in gunfights, air strikes and tank battles beginning on Wednesday afternoon and running through the night.
Iraqi Health Ministry figures show April was the deadliest month for Iraqi civilians since last August, with 968 killed nationwide. It was the deadliest month for US troops since September, with 49 reported killed.
A health official in Baghdad said 11 dead and 72 wounded had been brought to Sadr City's two hospitals in the past 24 hours. Victims included some women and children, but he did not say how many.
Most of the fighting has taken place in the Sadr City slum, where armed groups loyal to anti-American Shi'ite cleric Moqtada al-Sadr have been battling US and Iraqi troops since late March.
Some of the fiercest fighting has taken place in the past three days, with militiamen taking advantage of blinding dust storms that ground U.S. Apache attack helicopters to launch large-scale ambushes on US and Iraqi positions.
{{/usCountry}}Some of the fiercest fighting has taken place in the past three days, with militiamen taking advantage of blinding dust storms that ground U.S. Apache attack helicopters to launch large-scale ambushes on US and Iraqi positions.
{{/usCountry}}In one engagement, the military said US forces had opened fire on militiamen they caught loading rockets onto a launch sled late on Wednesday, killing six, including one who fled and then came back to try and salvage the rockets.
Since the crackdown on the Shi'ite fighters began in March, militants have fired salvoes of rockets across the capital, including into the heavily fortified Green Zone diplomatic and government compound.