BAGHDAD (Reuters) - Supporters of Iraq’s powerful Shi’ite Muslim cleric Moqtada al-Sadr began a sit-in outside the walls of Baghdad’s fortified Green Zone on Friday to press the government to see through a move to stem endemic corruption.

Leveraging his ability to mobilize grassroots pressure on the government, Sadr wants Prime Minister Haider al-Abadi to replace cabinet ministers with non-party technocrats to tackle systemic political patronage that has fostered graft.

Sadr rejected calls to cancel the sit-in prompted by fears of clashes between his supporters and security forces guarding the highly sensitive Green Zone, which hosts major government offices and foreign embassies in the Iraqi capital.

There were no reports of disturbances. A senior Sadr aide, Ibrahim al-Jabri, said the protest would last for 10 days if needed, until the end of a 45-day deadline Sadr gave on Feb. 12 to Abadi for a cabinet overhaul.

Corruption is eating away at the central government’s financial resources at a time when revenues are declining due to rock-bottom oil prices and Abadi needs to increase funding the U.S.-backed war against Islamic State militants.

Abadi on March 11 asked political blocs in parliament and “influential social figures” to nominate technocrats, but his room for maneuver appears limited by pressure from political factions not to erode their powerful influence.

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GREEN ZONE

The Green Zone was originally set up in 2003 to protect U.S. occupation forces that had toppled Saddam Hussein from suicide bombings and other Islamist militant attacks, and has been kept in place by successor Iraqi authorities for security reasons.

Thousands of demonstrators held Friday prayers in a main street leading into the Green Zone nearby, then set up tents to accommodate those staying on for the sit-in.

The Interior Ministry said it had not granted approval for the sit-in and riot police initially blocked roads and bridges leading to the Green Zone, before relenting and allowing demonstrators to march almost to its entrance.

On al-Jumhuriya (Republic) Bridge, riot police moved aside and let the demonstrators pull aside barbed wire barriers. “Let’s get rid of them, they’re all thieves!” they shouted as they advanced across the Tigris River span.

Waving Iraqi flags, the protesters also chanted, “Yes, yes to Iraq; no, no to corruption!”

Sadr published a statement on his website thanking the police for “their cooperation and devotion to their people.”

On Thursday, he branded the Green Zone “a bastion of support for corruption” but also asked followers to refrain from any violent reaction should they be stopped by security forces.

Authorities beefed up security around the sprawling capital, deploying additional checkpoints and police patrols, amid fears that the Shi’ite crowds could be attacked by Islamic State, whose Sunni militants hold swathes of northern and western Iraq.