A suicide bomb attack on a security checkpoint killed six people at an area 30 miles from Libyan city Benghazi.
At least eight people were reported to have been injured in the attack.
In recent months, the security situation in Benghazi has been worsening, with extremist militia blamed for frequent attacks.
Earlier in December, three soldiers and an American teacher were killed in the city in separate incidents.
In November, nine people died in clashes between the Libyan army and an Islamist militia, Ansar al-Sharia.
Benghazi has witnessed the rise of several extremist militia groups operational in the city since the civil war in 2011 that toppled Col Muammar Gaddafi.
Militias took part in the uprising that led to the fall of Col Gaddafi but have been told by the interim government to disband or join the army by the end of the year.