A Lebanese security official says an explosion has taken place in a predominantly Shiite suburb south of Lebanon's capital, Beirut.

The official says said the blast was heard on Thursday evening near a security office in the suburb of Burj al-Barajneh.

The official said the nature of the explosion was not immediately clear. The official spoke on condition of anonymity in line with regulations.

The southern suburb of Beirut is a stronghold of the militant Hezbollah group and has been hit by several bombings in the past that have killed dozens.

Hezbollah's Al-Manar TV says there were two explosions, about seven minutes apart, in the suburb's area of Burj al-Barajneh.