LONDON- Libya's El Feel oilfield has been shut down due to a valve closure, the head of the National Oil Corporation said on Thursday, in the second stoppage at the south-western field in consecutive weeks.

The NOC said the valve that was shut was on the export pipeline from El Feel, which runs hundreds of kilometres from the field to the Mediterranean coast in the north.

The statement did not give the location of the valve.

"Unfortunately we lost 73,000 barrel per day today," Mustafa Sanalla said in Vienna, before a meeting of the Organization of the Petroleum Exporting Countries.

"This is another criminal attempt to disturb the work of NOC and it harms the Libyan economy," the NOC later quoted Sanalla as saying in a statement.

El Feel is operated by Mellitah Oil and Gas, a joint venture between the NOC and Italy's Eni.

The interruption follows another stoppage at El Feel last week caused by clashes between groups aligned with rival political factions vying for control of the capital, Tripoli. 

Libya's national production is currently around 1.25-1.3 million bpd, Sanalla said on Wednesday.

In recent years, the country's oil output has been interrupted by blockades, attacks and protests at various fields, pipelines and ports, though in recent months production has been relatively stable.

(Reporting by Shadia Nasralla in Vienna; Writing by Ahmad Ghaddar and Aidan Lewis; Editing by Edmund Blair and Jane Merriman) ((Ahmad.Ghaddar@thomsonreuters.com; +442075424435; Reuters Messaging: ahmad.ghaddar.thomsonreuters.com@reuters.net))