Fierce clashes between Shiite gunmen and troops spread to new Shiite areas of Iraq on Saturday as the overall death toll from five days of bloodshed surged to nearly 230.
Saturday's violence was reported from the central Shiite city of Karbala in which 12 "criminals" were killed, local police chief Raed Jawdat Shakir said.
He did not provide further details, but said 25 people were also arrested in the operation that began on Friday night.
The death toll from similar clashes between Shiite gunmen and Iraqi and US troops in Baghdad's sprawling Sadr City stronghold rose to at least 75, with another 498 people wounded in the past four days.
"Seventy-five people have been killed and 498 wounded in clashes in Sadr City in the last four days," Qassim Mohammed, a spokesman for Baghdad health directorate, told reporters in Sadr City.
He accused the US forces of "creating obstacles" in transporting victims of the violence outside the area.
"They are preventing even international aid workers to help the wounded," he said during a visit to Sadr City's Imam Ali hospital.
Sadr City, bastion of the feared Mahdi Army militia of anti-American cleric Moqtada al-Sadr, has been engulfed in fierce clashes between security forces and the militiamen.
Clashes erupted in Baghdad after Iraqi Prime Minister Nuri al-Maliki launched a crackdown on Shiite fighters in the southern city of Basra on Tuesday.
Ahmed, a resident of the slum neighbourhood of some two million people, said the situation was deteriorating.