Explosion (illustrative)
Explosion (illustrative)Flash 90

At least 40 people were killed Thursday in an explosion at a weapons depot in southern Libya, local officials said.

According to the BBC, the blast is believed to have occurred after a group of people, reportedly including African immigrants, were trying to steal copper.

A hospital near the depot in Brak al-Shati, located near the city of Sabha, said it is treating the injured.

It is not clear what exactly caused the blast at the weapons depot, some 650km (400 miles) south of Tripoli.

State television reported that African immigrants were among a group of civilians who had stormed the depot in an attempt to steal the ammunition so they could remove its valuable copper.

General Mohamed al-Dhabi told AFP that "a group of unknown people tried to attack the depot, causing this unfortunate incident".

Meanwhile, four soldiers have been killed in another day of violence in the restive eastern city of Benghazi, reported the BBC.

In one incident, three naval officers were killed, and six others were injured, in clashes with members of the Salafist group Ansar al-Sharia.

Fighting broke out after naval officers arrested four people at their checkpoint when "a vehicle search found weapons and money", the army's special forces commander in Benghazi, Wanis Abu-Khamada, said.

Earlier Thursday, a soldier was reportedly shot in the head in a drive-by shooting in another part of Benghazi.

On Monday, at least three people were killed in clashes in Benghazi between the Libyan army and members of Ansar al-Sharia, the same group suspected in the murder of U.S. Ambassador Christopher Stevens last year.

Ansar al-Sharia is a coalition of Salafi and other Islamist fighters which calls for the implementation of Sharia (Islamic law) throughout Libya.

The name "Ansar al-Sharia" (literally "Partisans of Islamic Law") is a label commonly adopted by groups with similar ambitions elsewhere in the Muslim world.

The government in Libya has struggled to contain militias in control of parts of the country, and Benghazi has seen an increasing number of clashes between the army and militias.

The militias took part in the uprising that led to the fall of Muammar Qaddafi in 2011 but have been told by the interim government to disband or join the army by the end of the year.

A series of clashes in the Libyan capital killed dozens and wounded hundreds more last week, although tensions there appeared to cool after a number of militias agreed to surrender their bases to government forces.