BAGHDAD : Thousands of supporters of Iraqi cleric Moqtada Sadr defied a government ban Friday to launch sit-ins at the main gates of Baghdad's Green Zone aimed at pushing for reforms.

Many of the demonstrators carried Iraqi flags as they muscled past tight security and set up tents to begin what they said was an open-ended protest. "The sit-ins have started in front of the Green Zone gates as a message to the corrupt people who live there," Ibrahim al-Jaberi, a local official from Sadr's movement, told AFP.

The Najaf-based Sadr has called on his supporters to remain in front of the fortified "Green Zone" until his demands are met. The young Shiite cleric has demanded Prime Minister Haider al-Abadi reshuffle the cabinet to bring in technocrats and threatened a no-confidence vote if he failed to do so soon. "The sit-in is open-ended," said Jaberi, as Sadr followers started setting up camp on the streets and under trees.

The vast restricted area in the heart of the city is home to most key institutions, including the prime minister's office, parliament and the US embassy, which is the world's largest.

Demonstrators chanting slogans such as "Yes, yes to reforms" moved to crossroads around the Green Zone and started setting up tents, rolling out mats and pulling blankets out of bags. "We'll stay days, weeks or months if needed, until the government implements reform and sacks all the corrupt politicians," said one demonstrator, Muntadher Kadhem, a 25-year-old history student.

Sadr promptly issued a statement claiming victory in his tussle with the authorities and thanking God "for letting the will of the people triumph".