Libya's state-owned NOC declared force majeure at its 120,000 b/d Zawiya refinery today following clashes between armed groups near the facility.
NOC said a number of storage tanks were hit, causing fires. These were subsequently brought under control, it added.
Zawiya is Libya's largest operational refinery, with most of its production absorbed domestically. It runs on crude from Libya's Repsol-led El Sharara oil field.
The rest of the field's crude is exported as the Esharara grade from a nearby loading terminal which forms part of the wider Zawiya complex.
Any prolonged fighting and wider damage to the Zawiya complex could threaten production at El Sharara, particularly if exports are forced to stop.
Zawiya exported 160,000 b/d of Esharara crude last month, according to Kpler, and is scheduled to load eight cargoes also worth about 160,000 b/d in December.
Political instability has led to several forced shutdowns of oil production facilities over the past decade or so. El Sharara only just returned to production in early October following a forced outage which also affected other fields throughout the country.
Libya produced 1.24mn b/d of crude in November, Argus estimates.