A large blast has hit the Lebanese capital, Beirut, causing widespread damage and injuring many people, officials said.
Reports say the explosion was in the port area of the city, with unconfirmed reports of a second blast. It is not clear what caused them.
Video posted online showed a large mushroom cloud and destroyed buildings.
It comes at a sensitive time, ahead of the verdict in a trial over the killing of ex-PM Rafik Hariri in 2005.
A UN tribunal is due to issue its verdict in the trial of four suspects in the murder by car bomb of Hariri on Friday, as reported by BBC.