A day after al-Sadr announced the formation of his "Iraqi government" in defiance of the US-led occupation, a large crowd gathered in the city of Najaf, pledging their whole-hearted support.
"We are ready to sacrifice our souls for you, Sadr," chanted the demonstrators as they roamed the streets of the city.
A firebrand cleric, al-Sadr had announced the formation of the government during his weekly sermon in the town of Kufa.
"I have decided and I have formed a government made up of several ministries, including ministries of justice, finance, information, interior, foreign affairs, endowments and the promotion of virtue and prevention of vice," the young cleric had said.
"If you agree, I ask you to demonstrate peacefully in order to express you support," al-Sadr had exhorted.
Responding to his call, the crowd in Najaf registered their noisy support.
"...I have formed a government made up of several ministries, including ministries of justice, finance, information, interior, foreign affairs, endowments and the promotion of virtue and prevention of vice"
"We are against the American occupation forces and we back everything that Moqtada al-Sadr says," one of the demonstrators said.
The day's show of solidarity for al-Sadr coincided with more resistance attacks in the troubled country.
An Iraqi police officer was killed and six policemen wounded in a hand grenade attack near the town of Karbala, south of Baghdad.
Meanwhile, thousands of Iraqi Shias have begun to converge on the city of Karbala to celebrate the birthday of the 12th Imam.
They travelled from across the country to participate in the celebration of the birth of the ninth-century Imam al-Mahdi.
The authorities expected as many as five million Shias to make their way into the city for the occasion.