BENGHAZI, Libya  - Repairs to a pipeline operated by Libya's Waha Oil Co that was damaged by fire due to an attack are expected to take "a few days", National Oil Corp said on Sunday.

NOC said the expected loss of production would be 80,000 barrels per day (bpd) after the fire broke out at an isolation valve 21 km (13 miles) from North West Marada on Saturday.

NOC and an engineer at Es Sider port, which the pipeline feeds, said the fire had been brought under control in the early hours of Sunday. "Early investigations indicate that the fire was started as a result of sabotage," NOC said in a statement.

"Waha Oil Co maintenance teams have started work on the pipeline, with repair work estimated to complete within a few days."

Militants were blamed for a previous attack on the pipeline in December, when NOC reported a similar production loss of 70,000-100,000 bpd.

Libya's oil infrastructure has been repeatedly targeted by militants in recent years. Fighters loyal to Islamic State are in the area south of the country's oil crescent, which includes Es Sider, according to Libyan and Western officials.

The pipeline was repaired within a few days after the December attack and output returned to normal levels.

(Reporting by Ayman al-Warfalli and Aidan Lewis Writing by Aidan Lewis Editing by Dale Hudson and Andrew Heavens) ((Aidan.Lewis@tr.com; +216-29850352;))