“I make a historical call to every honest, reform-loving Iraqi to rise up and start a new phase in the peaceful popular protests,” the statement said.
Sadr urged protesters to stay there for the 10 remaining days of an ultimatum he gave the government last month.
“Get ready and organise yourselves to establish sit-in tents. This is your time to root out corruption and the corrupt,” he said.
A month ago, Sadr gave Prime Minister Haider al-Abadi a 45-day deadline to present the names of technocrats for a new government.
Abadi has been pushing for a government of technocrats in a bid to revive reform pledges that he made last year but have remained largely a dead letter.
Despite some of the ministers seen as the most corrupt being from his own political movement, Sadr has, with some success, attempted to make the new reform drive his own.
Sadrists have held a series of massive rallies in central Baghdad, with thousands turning out on Friday for the latest protest to press their demands.
The presence a week earlier of armed Sadr supporters outside the Green Zone — where Abadi’s office, parliament and the US embassy are located — sparked intense security concerns.
In the protest that he attended in Baghdad two weeks ago, Sadr threatened that his supporters could storm the Green Zone if their demands were not met.
The Sadr rallies saw thousands of the Najaf-based cleric’s supporters and members of his Peace Brigades militia bused in from the south of Iraq.
They stifled what was left of a secular protest movement that also demonstrated against corruption but was launched last year over the lack of basic services such as water and electricity.