Sadr had stayed out of the limelight since leading failed uprisings last year in the southern city of Najaf and in Baghdad's Sadr City neighborhood. But he has stepped up criticism of the United States in recent weeks, mainly by organizing Saturday's protest, which fell far short of the 1 million people he hoped would assemble.
Officials organized the demonstration with the Iraqi Interior Ministry's promise of protection. A group of protesters and police spent all night securing the square. Roads in central Baghdad were closed to traffic as streets filled with people.
Sunni Muslim clerics also called on their followers to protest on the two year anniversary of the fall of Baghdad, but officials in the influential Association of Muslim Scholars refused to say Saturday where or when the protests would take place. Iraq's Sunni minority was dominant under Saddam and is believed to make up the backbone of the country's insurgency.
Jalil al-Shemari, a senior Sadr official, said the Sunnis would not be joining in the Shiite rally at Firdos Square.
During his Friday morning sermon in the capital, the head of an influential Sunni group accused coalition forces of "killing the Iraqi people daily."
"We demand that the occupation troops withdraw from Iraq. We don't want them to do it immediately, but we want them to set a timetable for their withdrawal," said Sheik Harith al-Dahri, whose Association of Muslim Scholars is believed to have ties to Iraq's insurgents.
Other marches were held across the country to demand that the United States set a timetable for its withdrawal. In the central city of Ramadi, thousands of protestors demonstrated in the al-Sufayaa neighborhood and at Anbar University, demanding that U.S.-led coalition forces set a withdrawal date.
Also Saturday, in the troubled northern city of Mosul, a car bomb detonated near a police patrol, killing at least two policemen and injuring 13 civilians, Dr. Baha al-Deen al-Bakry of the Jumhouri hospital said.
Brig. Gen. Watheq Ali, deputy police chief of the Nineveh province, said the blast was an assassination attempt against him, although he was unhurt. He said a suicide car bomber rammed a car into the rear vehicle in his seven-car police convoy as it was stopped at a traffic light.
