Iraqi security forces used tear gas and stun grenades to repel demonstrators on Friday morning who had marched towards government buildings in protest against corruption and economic hardship.

The incident marked a renewal of the anti-government protests after security forces killed about 150 people in confronting a round of demonstrations at the start of the month.

About 1,000 people, some of whom had camped overnight in Baghdad's Tahrir Square, were marching towards the city's fortified Green Zone, which houses government buildings and foreign embassies, when they were stopped by security forces.

Medical sources told Reuters about 20 people had been treated in hospital for tear gas exposure.

Iraqi Prime Minister Adel Abdul Mahdi said in an address on Thursday that people would be free to exercise their right to demonstrate but that violence would not be tolerated.

Abdul Mahdi has struggled to address discontent since sometimes violent unrest erupted in Baghad on October 1 and spread to southern cities. Demonstrators blame corrupt officials and political elites for failing to improve their lives.

Despite the OPEC member's vast oil wealth, many Iraqis live in poverty, have limited access to clean water, electricity, basic healthcare or decent education as the country tries to recover from years of conflict and economic hardship.

Demonstrations continued for several days at the beginning of the month despite a violent crackdown by security forces.

A government committee set up by Abdul Mahdi said on Monday that 149 civilians were killed because security forces used excessive force and live fire to quell the protests. It recommended the dismissal and trial of dozens of senior security commanders.

Protesters, who have called on the ruling class to step down, gathered again in several cities on Friday morning after a two-week hiatus.

Abdul Mahdi said in Thursday's address that a government collapse would drag Iraq into further turmoil.“The resignation of the government today without a constitutional alternative, will lead the country into chaos,” he said.

He also reiterated reforms announced in the aftermath of the protests, including a cabinet reshuffle, opportunities for unemployed youth, a new court to try corrupt officials, as well as the halving of government salaries, including for top officials.