Those efforts continued into Sunday, with security forces using live rounds and tear gas to try to flush protesters out of squares and streets they had occupied for months.
In Baghdad, at least one person was killed and more than 30 injured in clashes between police and protesters near Tahrir Square.
Main roads in Baghdad were barricaded by security forces and the city's Green Zone, which houses foreign missions, were blocked off with concrete barriers.
The city's military command announced it had retaken control of Baghdad's Ahrar Bridge, a flashpoint for clashes between security forces and demonstrators for months.
In a statement Friday, al-Sadr - whose followers fought USA troops after the 2003 US -led invasion to oust dictator Saddam Hussein - issued a list of conditions for American military presence in Iraq.
Al Jazeera's Imran Khan, reporting from the protest, said the turnout was a "real show of strength".
Three French nationals and one Iraqi working for a French non-governmental organisation have gone missing in Baghdad, their employer said on Friday (Jan 24), adding that no ransom money had been demanded.
The march was called by Moqtada al-Sadr, who has recently aligned himself more closely with Iran.
Three children found dead in house outside Dublin
Police are investigating the "unexplained" deaths of three children whose bodies were discovered in a home in Co Dublin. The youth was taken from the scene by vehicle to Malahide Garda Station where he was treated by Garda ASU members.
Unrest resumed last week, after a lull of several weeks, following the USA killing of Iranian Major-General Qassem Soleimani and an Iraqi paramilitary chief in Baghdad this month.
Saturday's violence comes a day after a separate massive rally in Baghdad against the presence of USA forces in the country.
Activists said the presence of Muqtada Al Sadr's followers and his militia group had shielded the protesters from security forces and unknown groups looking to harm and suppress them.
Some sadristas traveling to Baghdad from southern Iraq to participate in Friday's rally against the USA military presence in Iraq said they were insulted or even blocked by non-Sadristas when they tried to join.
Sadr's supporters have bolstered the protesters and at times helped shield them from attacks by security forces and unidentified gunmen, but began withdrawing from sit-in camps on Saturday following his announcement.
No Iraqi or U.S. forces were killed and Trump had insisted no one was wounded either, but the Pentagon on Friday said 34 American soldiers had suffered traumatic head injuries or concussions.
Iraqi cleric Moqtada al-Sadr has suspended his involvement in anti-government protests.
"I am expressing my disappointment and my regret toward all those who doubted me among the Tahrir Square protesters", he said in a tweet Friday evening.
The missiles hit Baghdad's heavily-fortified Green Zone, AFP said, citing security sources.