A Libyan soldier was shot dead and three others badly wounded when gunmen attacked an army patrol in the eastern city of Benghazi late Tuesday, a security official said.
The assailants escaped after opening fire on the patrol from a car, the official told AFP.
One soldier was killed and "the three injured men are in critical condition", he added.
Benghazi, the birthplace of the 2011 Libyan revolution, has seen several bombings and attacks against security services and Western diplomatic missions in recent months, highlighting the inability of the authorities to establish effective security in the country.
These attacks are usually blamed on radical Islamists, like the one last September 11 against the US consulate which killed four Americans, including ambassador Chris Stevens.