An arms depot of the Iran-backed Hezbollah that exploded in southern Lebanon on Tuesday, injuring several people, was caused by a “technical error”, a security source said.
The blast sent a huge column of black smoke into the sky and rocked the southern village of Ain Qana, above the port city of Sidon.
The area is a political stronghold of the heavily armed and politically powerful group, which has fought wars with neighbouring Israel.
A witness near Ain Qana said they felt the ground shake.
There has been no official confirmation of the cause of the blast.
A Hezbollah official told The National that the building destroyed in the blast had been the office of a demining organisation. While the official declined to give further detail, other reports cited Hezbollah officials saying that the building belonged to a demining group associated with the party and that the weapons stored there were leftover from previous wars.
Members of the group imposed a security cordon barring journalists from reaching the area.
Footage broadcast by the local Al Jadeed television station showed damage to buildings.
Newspaper The Daily Star quoted security sources saying there were four casualties.
The blast stirs new worries in Lebanon, a nation grappling with its worst crisis since the 1975-1990 civil war.
It also comes seven weeks after the massive explosion at Beirut port, in which about 3,000 tonnes of improperly stored ammonium nitrate was detonated.
The blast killed more than 190 people, injured 6,500 and damaged tens of thousands of buildings in the Lebanese capital.
It is not known what ignited the chemical, and no one has been held accountable.