Iraqi officials say at least 12 people were killed in fierce fighting in Basra province on Tuesday, as government security forces and Shi'ite militias battle for control of the oil-rich southern port.
At least 18 others were wounded during the first day of an Iraqi military operation targeting militants in the south.
Iraqi Shi'ite cleric Moqtada al-Sadr is urging his followers to stage protests against recent raids and detentions targeting his Mahdi army.
One of Sadr's aides, Hazem al-Aaraji read a statement today saying the radical cleric would order a "civil revolt" if attacks against his followers were not halted immediately.
The clashes are jeopardizing a seven-month-old cease-fire that Sadr declared last year.
In an interview with VOA's Kurdish service, a member of Iraq's parliament from the Sadr bloc, Baha al-A'raji, called on supporters of the Sadr movement to use caution and avoid further inflaming tensions.