Officials say the demonstrators were killed at capital Baghdad's Rasheed Street in ongoing clashes with security forces.
Iraqi officials said on Friday that four protesters were killed and 25 wounded amid ongoing clashes with security forces near a strategic bridge in capital Baghdad.
Security and hospital sources said three people were killed on Baghdad's Rasheed Street in clashes with security forces.
Two protesters died because of tear gas, and one due to live rounds fired by security forces.
The officials requested anonymity in line with regulations.
The clashes come hours after some of the most violent clashes between anti-government protesters and security forces in recent days.
At least 10 protesters were killed on Thursday in clashes on the same street, which is very close to Ahrar Bridge.
Deadliest grassroots movement
After decades of back-to-back conflicts, Iraq is in the thick of its largest and deadliest grassroots protest movement, with more than 320 people dead and 15,000 wounded.
To disperse protesters, security forces have used tear gas, rubber bullets, flashbangs, live rounds and even machine-gun fire –– all of which have seriously maimed or even killed protesters.
Protesters are demanding the overthrow of a political class seen as corrupt and serving foreign powers while many Iraqis languish in poverty without jobs, healthcare or education.
Iraq's top Shia Muslim cleric, Grand Ayatollah Ali al Sistani, called on Friday for politicians to hurry up in reforming electoral laws because the changes would be the only way to resolve weeks of deadly unrest.
"We affirm the importance of speeding up the passing of the electoral law and the electoral commission law because this represents the country moving past the big crisis," his representative said during a sermon in the holy city of Karbala.
Entrance to key Iraqi port reopened
Also on Friday, security forces reopened the entrance to Iraq's main Gulf port after forcibly dispersing protesters who had been blocking it.
Employees were able to enter the Umm Qasr commodities port near Basra for the first time since it was blocked on Monday, port sources told Reuters news agency, but normal operations had not yet resumed, the sources said.