At least four anti-government protesters were killed and 90 injured when security forces ejected them from Baghdad's heavily fortified Green Zone, hospital sources said on Saturday.
Iraqi security forces used live ammunition, rubber bullets, water cannons and tear gas on Friday to dislodge the demonstrators from the central district which houses government buildings, parliament and many foreign embassies.
The toll, compiled from four hospitals where casualties were taken and Baghdad's central morgue, accounts only for gunshot wounds and does not include cases of suffocation caused by tear gas.
Civilians have breached the Green Zone twice in three weeks, raising questions about the government's ability to secure the capital which has also seen a spike in bombings this month claimed by Islamic State.
Protesters on Friday included supporters of powerful Shi'ite Muslim cleric Moqtada al-Sadr and people from other groups upset with the government's failure to approve anti-corruption reforms and maintain security in the city.
Jaafar al-Moussawi, deputy leader of Sadr's political movement, condemned the government for using what he called "excessive force".
"Using live bullets against peaceful protesters is completely unjustified and stark evidence that a supposedly legitimate government has turned into an oppressive government," he said in a statement on Saturday.
Prime Minister Haider al-Abadi has condemned the Green Zone breach and warned against chaos and strife as government forces seek to keep up momentum against Islamist militants.
The United Nations expressed "deep concern" on Saturday about the incident and warned it could hamper efforts to defeat Islamic State, the ultra-hardline Sunni group that controls large swathes of territory in northern and western provinces.
"Only the enemies of Iraq, Daesh at the forefront, benefit from chaos," U.N. Special Representative for Iraq, Jan Kubis, said in a statement, using an Arabic acronym for Islamic State.