Offices of the Association of Lebanese Banks were also trashed during the protests.
The scene in Beirut is one of the increasingly angry demonstrations as Lebanese citizens express their frustration and fury over its government’s negligence in this week’s devastating explosion.
Protesters have called for their politicians to resign and be punished for turning a blind eye that led to Tuesday’s blast — the biggest to ever hit Beirut.
Around 158 casualties and 6,000 injuries result from the Beirut explosion have so far been reported, compounding months of political and economic meltdown.
A policeman was killed during the clashes, a spokesman said. A policeman at the scene said the officer died when he fell into an elevator shaft in a nearby building after being chased by protesters.
The Red Cross said it had treated 117 people for injuries on the scene while another 55 were taken to hospital.
Policemen wounded by stones were treated by ambulance workers. A fire broke out in central Martyrs' Square.