Lebanon’s Interior Minister Mohammed Fehmi said the huge explosions may have been caused by explosive materials that were stored at Beirut port.
General Security chief Abbas Ibrahim said: “It appears that there is a warehouse containing material that was confiscated years ago, and it appears that it was highly explosive material”.
Speaking to reporters, he said a probe would begin, but added: “we cannot preempt investigations”.
The head of the Lebanese Red Cross told local media that hundreds of people have been injured in the explosion.
Georges Kettaneh said he could not put a more exact figure on the number of people wounded because many were still trapped in the area of the blast.
He told Lebanon’s LBC television that the Red Cross had been “overwhelmed” with calls since the explosion.
The group said all of its available ambulances had been dispatched to help with rescue efforts.
Hospitals are also said to be overwhelmed with casualties.
AFP correspondent Maya Gebeily said some were turning away injured people because they were too full.