(Adds details on attack, U.N. statement)
BENGHAZI, Libya, Nov 27 (Reuters) - Forces based in eastern Libya said on Wednesday they had driven rival factions from the 70,000-barrel-per-day (bpd) El Feel oilfield after attacking the area with air strikes, leading to production being halted.
The eastern-based forces had counter-attacked after forces aligned to the internationally recognized government in Tripoli took control of the field earlier in the day.
The Libyan National Army (LNA) drove out the rival group and was securing the field, LNA spokesman Ahmed Mismari said on his Facebook page.
The fighting reignited a conflict for control of large oilfields in southwestern Libya between competing military alliances that are also battling on the outskirts of the capital, Tripoli.
"There have been air strikes at the gates of the El Feel oilfield and inside a housing compound at the field used by NOC personnel," Mustafa Sanalla, Chairman of Libya's National Oil Corporation (NOC), said in a statement.
"Production will remain shuttered until military activity ceases and all military personnel withdraw from NOC's area of operations."
The LNA, led by Khalifa Haftar, said its jets carried out air strikes "at the perimeter of El Feel oilfield targeting the positions of armed groups that attacked the field." They said they had destroyed some of their rivals' vehicles.
Some staff had left the field during the clashes, an engineer said.
Libya has been divided since 2014 into rival military and political camps based in Tripoli and the east. Haftar controls most of Libya's oil fields and facilities but oil revenues are controlled by the central bank in Tripoli.
Libya's oil production has been repeatedly disrupted in recent years by conflict and blockades but is currently relatively stable at about 1.25 million bpd.
The U.N. mission to Libya, which has led international peace efforts, expressed "grave concerns" over the violence at El Feel.
El Feel is operated by Mellitah Oil and Gas, a joint venture between the NOC and Italy's Eni. An engineer at the field said production was 70,000 bpd before the stoppage.
Haftar's forces have controlled El Feel and the nearby El Sharara oilfield, Libya's largest, since February, when they swept through the south before launching an offensive on Tripoli in April. (Reporting by Ayman al-Warfalli; additional reporting by Ahmed Tolba; Writing by Aidan Lewis and Yousef Saba; Editing by Kirsten Donovan and Grant McCool)