Beirut has been rocked by a huge explosion ahead of the verdict in a trial for the killing of ex-PM Rafik Hariri.
Reports say the blast in the capital of Lebanon took part in the port area of the city and left people covered in glass and blood.
The Lebanese health minister has reported a "high number of injuries".
There are unconfirmed reports of a second blast.
Lebanon's state news agency NNA and two security sources said the blast happened at warehouses housing explosives.
It was not immediately clear what caused the blast or what kind of explosives were in the warehouses.
A witness told Reuters: "I saw a fireball and smoke billowing over Beirut. People were screaming and running, bleeding.
"Balconies were blown off buildings. Glass in high-rise buildings shattered and fell to the street.
Local broadcaster LBC quoted the health minister as saying there was a "very high number" of injures and a large amount of damage.
Al Mayadeen television said hundreds were wounded.
Another Reuters witness said she saw heavy grey smoke near the port area and then heard an explosion and saw flames of fire and black smoke.
She added: "All the downtown area windows are smashed and there are wounded people walking around. It is total chaos."
