Iraq's military has imposed a curfew in Baghdad "until further notice", state television said in a newsflash after security forces opened fire at protesters who had entered the heavily fortified Green Zone, Al Arabiya reported.
Earlier on Friday, anti-government protesters stormed Baghdad's Green Zone for the second time in less than a month, despite the tear gas fired by security forces.
Witnesses said dozens of people were injured. The protesters included supporters of powerful Shiite cleric Moqtada al Sadr and people from other groups who are displeased with the government's failure to approve anti-corruption reforms and provide security.
Friday's violence comes more than two weeks after the highly fortified compound was first breached by Shiite protesters in April.