Image copyright AFP Image caption The blast occured in a dockyard belonging to the Beirut Port Authority
The explosion that injured 30 people, including children, at Beirut’s port has come at a sensitive time in the country.
In a month that has seen Lebanon shaken by sectarian violence, the blast also threw up a new threat to the government of the prime minister-designate Saad Hariri, who has been beset by corruption allegations.
The port is run by the Port Authority and is a major logistical hub for the country’s ports, which also include the island of Tripoli and its port.
The government said it had launched an investigation.
Mr Hariri is seeking to form a government as the country tries to recover from the 15-year civil war which broke out in 1975.
Witnesses described the flames leaping from the dock as the bomb exploded at about 05:00 local time (01:00 GMT). The blast shattered windows on nearby buildings.
The bomb could have caused “considerable” casualties if it had been bigger, said Qassem Adib, a senior police officer.
State TV said security forces had combed the area for other possible remnants of the bomb.
‘Shame on all Lebanon’
The blast happened less than a month after one targeting the Radwan mosque in the Muslim quarter of Beirut. It killed 29 and injured over 50 people.
On Friday, a bomb was also detonated near the Sayyed al-Shuhada Mosque in Beirut, killing two people and injuring five.
According to its website, the Radwan mosque has a historical site dedicated to Imam Hussein, a Shia figure from the 12th century.
The death toll from the bombing was originally reported as 33 but local media reported that it may have been higher.
In recent years, Hezbollah, a Lebanese Shia group allied to the Iran-backed Syrian government, has been accused of political assassinations in Lebanon, and of bombing the car in which the country’s former prime minister Rafiq Hariri was killed, in 2005.
The current head of Hezbollah has rejected accusations of involvement in recent assassinations, saying that they are in fact motivated by rumours about his group.
Before the blast, the port authority had said the port was open as usual
Social media users quickly blamed Israel, which according to unofficial reports attacked Beirut in 2008 and 1996, as well as suicide attacks in 1995.
However, the current government led by Saad Hariri has been plagued by corruption allegations, raising the spectre of one of Lebanon’s worst civil wars returning to the country.
In an interview in March, Mr Hariri said he was the victim of an illegal assassination attempt. Four people were arrested in connection with the alleged plot, including three close allies of President Michel Aoun.
But two of the suspects were released days later after prosecutors were told by a judge that they had been tortured.
In July, Mr Hariri announced that the trial of Saad Hariri’s ally Samir Geagea, who is on trial for his role in the murder of the PM, was “finished”.