At least five people were shot dead at a protest in the Lebanese capital Beirut against the judge investigating last year’s devastating port explosion.
Heavy gunfire erupted as supporters of the Hezbollah and Amal movements demanded Judge Tarek Bitar’s removal.
They said snipers on rooftops attacked them to drag the country into strife.
Huge tension surrounds the probe into the port blast, with Hezbollah accusing the judge of unfairly singling out allied former government ministers.
What began as a protest against Judge Bitar outside the Palace of Justice, with chanting and marching, escalated significantly.
Heavy, rolling gunfire erupted in the streets as the crowd passed through a roundabout in the central Tayouneh-Badaro area.
Bullets also landed near a local school, forcing students to duck for cover under their desks.
Hezbollah and Amal said in a joint statement that the protesters were targeted by “snipers positioned on the roofs of buildings”.
“This attack by armed and organised groups aims to drag the country into a deliberate strife, the responsibility of which must be borne by the instigators and the parties that hide behind the blood of the victims and martyrs of the port in order to achieve malicious political gains,” they added.
Prime Minister Najib Mikati called on everyone to “calm down and not be drawn into sedition for any reason whatsoever”.
The army said it had deployed troops to restore calm and search for the assailants, and warned that they would “shoot at any gunman on the roads and at anyone who shoots from any direction”.
Earlier, a court dismissed a legal complaint brought by two of the five politicians who Judge Bitar has sought to question on suspicion of negligence.
Families of the victims of the port explosion had condemned the move, which caused the investigation to be suspended for the second time in three weeks.
They allege that the country’s political leadership is trying to shield itself and senior officials from scrutiny.
No-one has been held accountable for the August 2020 disaster, in which killed 219 people were killed, 7,000 were wounded and thousands of buildings were destroyed or damaged.
A fire triggered the detonation of 2,750 tonnes of ammonium nitrate, a combustible chemical widely used as agricultural fertiliser, that had been stored unsafely in a port warehouse for almost six years.
Senior officials were aware of the material’s existence and the danger it posed but failed to secure, remove or destroy it.