Tens of thousands of supporters of al-Sadr rallied in central Baghdad on Friday to press demands for reform and an end to alleged corruption in the government.

"We are tired [of] corruption," Mohamed al-Daradji, an activist and filmmaker, said in a speech at the protest, "corruption is killing us."

The rally went ahead despite a warning from the central government that it could distract security forces from the war against the self-styled "Islamic State" group. A statement from the Joint Operations Command termed it "unauthorized" and said anyone who appeared with arms would be treated as a "terrorist threat." But followers of Al-Sadr ignored the threats and turned out en mass.

"Uproot them, they are all thieves," some chanted. A protester held a banner, reading: "We came out demanding reform, nothing else."

Iraqi security forces had warned people to stay away from the rally, saying the demonstration was 'unauthorised'

Thousands defy warnings to stay away from Tahrir Square

Al-Sadr has called for the dismissal and trial of corrupt officials, an end to sectarian and political party quotas through which positions are shared out, and the formation of a government of technocrats. But he cut short his address to the crowd and hurriedly left when crowds surged forward, threatening a potentially deadly stampede.

Al-Sadr has organized repeated protests calling for reforms, during which demonstrators have on several occasions breached Baghdad's Green Zone, a fortified area that is home to key government institutions and foreign embassies.

Al-Sadr commands a powerful Shiite militia that draws support from poor areas of Baghdad. Its forces battled US troops during their 2003-2011 military presence of Iraq.

In the past, security forces fired tear gas to disperse demonstrators at previous protests, but this was one was much more tightly stewarded by organizers.

Protesters were repeatedly searched by men posted at makeshift checkpoints on the way to the demonstration, and strands of barbed wire kept them away from the bridge across the Tigris River that connects to the Green Zone.

jar/msh (AP, AFP)