3 guards were killed and 2 others wounded in an attack on checkpoint 60 in southern Ajdabiya on Tuesday.
Local sources said a suicide bomber exploded his car in the checkpoint which is run by brigade 152 of Dignity Operation early in the morning.
No group has claimed responsibility for the attack.
This is the second attack on the checkpoint in 3 months. In March, A suicide bomber struck his explosives-laden car in the checkpoint killing 3 guards.
Meanwhile, gunmen attacked the main checkpoint of Awjila town, northeastern Libya, on Tuesday.
The gunmen set the checkpoint on fire and abducted a policeman before escaping to the desert.