A large blast has hit the Lebanese capital, Beirut, causing widespread damage and injuring many people, officials say.
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.
The possible second explosion was reported to be at the Hariri residence in the city.
Lebanon’s health minister, Hamad Hasan, has spoken of many injuries and extensive damage.
Local media showed people trapped beneath rubble. A witness described the first explosion as deafening. Video footage showed wrecked cars and blast-damaged buildings.
The latest reports come amid political tension in Lebanon, with street demonstrations against the government’s handling the worst economic crisis since the 1975-1990 civil war.
There has also been tension on the border with Israel, which said last week that it had thwarted an attempt by Hezbollah to infiltrate Israeli territory.