The thousands of protesters in Tahrir Square "had nothing to do with this morning's events", it concluded.
The anti-government protests that have shaken Iraq for months took a brutal turn Thursday when protesters slaughtered a 16-year-old boy who had fired a pistol in the air to try to shoo them away from his family's home. Some videos circulating on social media showed him being beaten and dragged across the street.
The rare outburst of violence by the protesters underscored the increasing tension on the streets after the killing of more than 400 protesters by government forces and a recent spate of attacks by other groups, while the lack of a response by either the police or bystanders, many of whom recorded the killing on their cellphones, raised questions about the complicity of Iraqi society.
Last Friday 25 protesters were killed in Baghdad's Khilani Square.
Abductions of protesters and the assassinations of high- profile activists are rising.
Protesters largely blame Iran-backed militias for the attacks and see the violence as a campaign to instill fear and weaken their peaceful movement.
Iraq's top Shiite Muslim cleric on Friday condemned recent killings of anti-government protesters and urged full state control over the use of weapons in the country following one particular deadly attack by masked gunmen in Baghdad.
Safety officers mentioned was needed by police on drug-related prices and was working from safety forces on the time. An enraged mob beat the young man to death, security and health officials said. They requested anonymity in line with regulations.
He also called on the armed forces to remain professional, loyal to the state and free from foreign influence, a representative of Sistani said during a sermon on Friday in the holy city of Kerbala.
The Brigade is part of Saraya al-Salam, or Peace Companies, headed by the Shia cleric Moqtada al-Sadr.
A dispute between a teenager and protesters in Iraq culminated with the body of the youth being strung from a traffic light near Tahrir Square.
Demonstrators in Iraq lynched a teenager accused of attacking a protest encampment in Baghdad on Thursday, police and witnesses said, in an attack that threatened to tarnish the protest movement's broadly non-violent image.
"What happened today in Al Wathba Square is a crime condemned by demonstrators and condemned by humanity and religions and punishable by law", the organizers told ABC News.
Separately, two rockets were fired at a military base near Baghdad airport housing U.S. troops, the 10th such attack since late October, the Iraqi army said on Thursday.