Lebanon has announced a day of mourning for Friday after at least six people died and dozens were hurt in deadly fighting in Beirut.
Gunfire broke out during a protest by Shia Muslim groups against the judge investigating last year's huge blast at the city's port.
Hezbollah, which organised the protest, says demonstrators were fired on by gunmen on rooftops.
They blamed a Christian faction, although the group denies the charge.
Huge tension surrounds the inquiry into the port explosion that killed 219 in August 2020.
Swathes of the city were devastated by the blast, but no-one has yet been held accountable.
Hezbollah and its allies say the investigating judge is biased, but the victims' families support his work.
What began as a protest outside the Palace of Justice - the main court building - by hundreds of people arguing the investigation had become politicised and demanding the removal of Judge Tarek Bitar quickly escalated.
Heavy gunfire erupted in the streets as the crowd passed through a roundabout in the central Tayouneh-Badaro area.
Local residents had to flee their homes and schoolchildren ducked for cover under their desks as men armed with automatic rifles and rocket-propelled grenade launchers - believed to have been members of Shia and Christian militias - exchanged fire in the streets.
The clashes continued for several hours before calm was restored.
At a nearby school, teachers instructed young children to lie face down on the ground with their hands on their heads, a witness told Reuters news agency.
Hospital and military sources said some of those killed had been shot in the head. They included a woman who was hit by a stray bullet while inside her home.