An armed drone targeted the home of Iraqi cleric Moqtada Sadr on Saturday, hours after his supporters deployed in Baghdad in response to an attack that left 17 protesters dead.
The developments marked a worrying turn for the anti-government protests rocking Iraq since October, the country's largest and deadliest grassroots movement in decades.
The mostly young protesters in the capital's iconic Tahrir Square had long feared a spiral into chaos, and on Friday it appeared their apprehensions were well-placed.
After nightfall, armed men on pick-up trucks attacked a large building where protesters had been camped out for weeks near the capital's Al-Sinek bridge.
Security forces deployed on the bridge itself did not intervene, witnesses said, as the attackers ousted protesters from the building in a volley of gunfire.
At least 17 people were killed and dozens more wounded, medics told AFP, with ambulances shuttling teenagers suffering gunshot and stab wounds to nearby field clinics.
Panicked demonstrators rushed out into the street, sending out calls through social media for people to come to their main gathering place in Tahrir Square.
By Saturday morning, hundreds had arrived.
"I came after the incident and there were tons of people in Tahrir and by Al-Sinek," one demonstrator told AFP.
