Libya’s National Oil Corporation (NOC) has warned that it could declare force majeure and halt operations at the Zawiya refinery if drone attacks on oil facilities in the city continue, according to Reuters.

The attack targeted an oil blending and filling plant operated by Zawiya Oil Refining Company, falling near a main oil tank and pipeline network. No casualties or material damage were reported.

The incident was the third reported attack targeting oil assets in Zawiya on Sunday and Monday. No group has claimed responsibility for the attacks, and Libyan authorities have not identified those believed to be behind them.

Libya’s oil ministry said the affected tank contained around 4.5 million liters of gasoline and later collapsed.

The Zawiya refinery, located around 40 kilometers (km) west of Tripoli, has a capacity of 120,000 barrels per day (bbl/d) and is connected to the 300,000-bbl/d Sharara oilfield. It is currently Libya’s largest operating refinery.

Libya has faced prolonged political and security instability since 2011 that left the country divided between two rival governments, leading to frequent blockades of oil fields by armed groups and protesters.