Libya's National Oil Corporation said fighting triggered a suspension of production Wednesday at a key field in the country's southwest.
Forces loyal to eastern Libya strongman Khalifa Haftar said they carried out air raids against "armed groups" that had attacked Al-Feel field.
Haftar's spokesman Ahmad al-Mesmari accused "militias" of the Government of National Accord (GNA) of being behind the attack.
Al-Feel produces some 70,000 barrels per day (bpd) in a joint venture between NOC and Italy's ENI.
The NOC said the air raids hit the entrance to the field and a housing compound used by staff.
"NOC staff at the field are protected in safe areas, but they cannot resume their normal duties," the firm's chairman Mustafa Sanalla said.
Production would remain suspended until military activity ceased and all armed personnel withdrew from the production area, he said.
The company posted on its Facebook page a video of the field showing a thick column of smoke, with the sound of combat clearly audible.
The United Nations Support Mission in Libya (UNSMIL) expressed "grave concerns" over the attacks, calling in a statement for "the immediate cessation of military operations" near the field.
"Obstructing the oil production will affect all Libyans across the country," UNSMIL wrote, adding that the country's oil infrastructure should remain under the "exclusive control of the NOC".
On Wednesday evening, Mesmari said there had been a "withdrawal of armed groups" following the air raids, without providing further details.
It was not immediately clear if pro-Haftar forces still controlled the site. Haftar's self-styled Libyan National Army seized the country's main southern oil fields -- including Al-Feel -- early this year in an operation it said targeted "terrorist groups".
The oil fields had previously been controlled by local tribes.
After its campaign in the south, the LNA in April launched an assault on the capital Tripoli, seat of the UN-recognised GNA.
Fighting on that front -- centred on southern Tripoli -- has not affected Libya's oil production, estimated at 1.25 million bpd.
Libya has been mired in chaos since a NATO-backed uprising that toppled and killed dictator Moamer Kadhafi in 2011.
Military clashes and political rivalries have often stymied oil production, the country's main source of revenue.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)