Production at the western Libyan fields of Sharara and Wafa has been blocked by armed factions, reducing output by 252,000 barrels per day (bbl/d), a source at the National Oil Corp. (NOC) said March 28.

The shutdown at Sharara, which had been producing about 220,000 bbl/d, began on March 27, and the shutdown at Wafa a day earlier, the source said.

Sharara resumed operations in December after a shutdown that began in November 2014 due local protesters blocking a pipeline connecting it to the Zawiya oil terminal.

Austrian oil firm OMV AG, one of the foreign partners in the field, is expected to load a 600,000 bbl cargo of Sharara crude from Zawiya on board the Sea Vine tanker later this week.

The tanker, which arrives at the port early on March 29, could still load its cargo from storage tanks, a Libyan port source with knowledge of the shipment told Reuters.

OMV did not immediately respond to a request for comment.

The oil field is operated by a joint venture between NOC and a consortium of Repsol SA, Total SA (NYSE: TOT), Statoil ASA (NYSE: STO) and OMV.