Iraqi security forces have fired tear gas and gunshots in the air as hundreds of protesters stormed Baghdad's heavily secured Green Zone, rushing toward the prime minister's office and the parliament building.

An Associated Press reporter at the scene saw several protesters badly wounded and one was shot in the head.

Friday's violence comes more than two weeks after the highly fortified compound was first breached by Shiite protesters in April.

Iraqi security forces at the time largely stood down, allowing protesters to scale walls and pull down concrete barriers. Prime Minister Haider al-Abadi later replaced the head of the compound security.

The initial breach followed repeated delays to proposed government reform legislation and has since left the country's government gridlocked and the parliament unable to convene.