It was the first time that Fajr Libya, a coalition of Islamist militias, carried out an air raid on the oil region of Al-Hilal, which is home to the Al-Sidra, Ras Lanuf and Brega terminals.
Ali al-Hassi, security spokesman for the region, told AFP that a warplane fired missiles at a sector to the west of Al-Sidra, without causing casualties or damage.
Anti-aircraft fire repelled the plane, which the official said could have been planning to target army planes and helicopters parked on a nearby landing strip operated by Ras Lanuf oil company.
Jets and helicopters over the weekend repelled advancing Islamist fighters, who also clashed on the ground with pro-government forces. No casualty figures were available from the fighting.
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In Tripoli, a car bomb exploded near the capital's security headquarters, without causing casualties, a security source said, declining to be identified.
Cars and buildings were damaged in the blast.
More than three years after dictator Moamer Kadhafi was toppled and killed in a NATO-backed revolt, Libya is still awash with weapons and powerful militias, and has rival parliaments as well as governments.
The United Nations Support Mission in Libya on Tuesday condemned the military escalation in Al-Hilal and called for an immediate ceasefire "to give the Libyan political dialogue a chance".