Among the fatalities, most died from bullet wounds, a hospital source said, adding that about 120 protesters were wounded. At least 57 members of the security forces were injured, according to another hospital source and a security source.
The clashes continued on Friday evening after a week of violence that erupted on Sunday when security forces fired to disperse protesters, who were trying to storm the provincial government building using rocks and Molotov cocktails.
Protesters are demanding the removal of the governor and justice for protesters killed since 2019.
Iraq's biggest anti-government protests in decades broke out in October 2019 and continued for several months, with hundreds of thousands of Iraqis demanding jobs, services and the removal of the ruling elite, whom they accused of corruption.
Nearly 500 people were killed, and the protests caused the resignation of Prime Minister Adel Abdul Mahdi.
Prime Minister Mustafa al-Kadhimi, who took office in May 2020, has pledged justice for activists killed or abused by armed groups. But no prosecutions have occurred so far.
The clashes come just a week before Pope Francis visits Iraq from March 5 to 8. He is due to tour the ancient Mesopotamian site of Ur, only about 20 kilometres away from the clashes.