East Libyan forces carried out airstrikes around major oil ports overnight as they sought to regain control of the area that a rival faction seized hours earlier, a military spokesman said on Saturday.
It did not detail any specific measures taken or say that there had been any change to operations in the ports.
The Benghazi Defence Brigades are composed partly of fighters who were ousted from Benghazi by the LNA, where LNA commander Khalifa Haftar has been waging a military campaign for almost three years against Islamists and other opponents.
That battle is linked to a wider conflict between political and armed factions based in eastern and western Libya.
After seizing key oil ports, Benghazi Defence Brigades has urged state authorities to take control of the oil crescent region.
Libya remains regionally split with two centres of power that politically oppose each other, and a myriad of rival armed groups that the country's two governments can not control.
However, an officer on Haftar's staff told AFP that MiG-23 warplanes and Mi-35 attack helicopters bombarded a convoy of Benghazi Defense Brigades vehicles south of Nofliya.
The spokesman of the LNA, Colonel Ahmad al-Mismari, said on Friday that it had retreated to avoid civilian casualties.
The army has deployed more forces in preparation of a counterattack to drive out the militias, known as Benghazi Defense Brigades, which are comprised of Islamic militants and former rebels recently defeated by Hifter's forces in Benghazi, Libya' second largest city, he said.
A resident in Ras Lanuf said they heard war planes over the town at dawn on Saturday, followed by explosions. The Tripoli-based National Oil Corp., which Hifter has allowed to operate the ports, held an emergency meeting to discuss how to proceed.