"The clashes between followers of the Hezbollah [movement], the Amal Movement and police are taking place on the Ring Bridge near the Martyr's Square and the Riad Al Solh Square. Police are using tear gas to prevent aggressive groups from access to peaceful demonstrators. Followers of the Shia parties are throwing stones to police officers", the eyewitnesses said.
Some Lebanese media also report that Shia activists were throwing Molotov cocktails at police officers.
That is not the first attempt of Shia activists to attack opposition demonstrators, whose camps were set on fire and looted.
People have remained in the streets of Lebanon since 17 October, despite premier Saad Hariri and his cabinet being dismissed, to demand economic reforms, specifically in the banking sector.
Before Hariri's cabinet resigned, both of the main Shia-based groups, Hezbollah and the Amal movement, were represented in the Lebanese government.