Libya's National Oil Corporation (NOC) has declared a force majeure on crude oil loadings at Zawiya port after sabotage.
Liftings were halted on Saturday after "an unlawful Sharara pipeline valve closure by an unidentified group between Hamada and the Zawiya port the previous evening."
Production was suspended.
Around 290,000 barrels per day (bpd) have been forced offline, with a value of $19m per day.
NOC chairman Mustafa Sanalla said: “Criminal activity has required NOC to declare force majeure at Zawiya.
"Deliberate attempts to sabotage pipelines and production hurt both national oil revenues and critical power supply for everyday Libyans.
"[NOC subsidiary] Akakus security personnel and engineers are investigating the incident and working to quickly restore production. The corporation, in partnership with relevant authorities, will find and prosecute those responsible for this unnecessary interruption.”
Earlier this month, Libyan military leader Khalifa Haftar said NOC in Tripoli has the "exclusive" right to export oil, in a move that could stabilise the country's production.
Last year, the commander of forces in the east of the country briefly handed control of key ports to another NOC based in the east as part of the ongoing problems caused by its civil war.
Haftar pledged to continue to protect oil facilities while urging NOC not to work against his army.
