Libya's National Oil Corporation (NOC) has declared a force majeure at the Sharara oil field after militia seized it over the weekend.

It blamed ‘civilians’ attached to the Petroleum Facilities Guard (PFG), alleging physical threats were made to oilfield employees to get them to halt production.

The shutdown of Sharara will result in a daily loss of 315,000 barrels a day, with an additional loss of 73,000 barrels at El Feel due to its dependence on Sharara for electricity supply.

Production at the Zawiya refinery is also at risk due to its dependence on crude oil supply from Sharara. NOC said.

The combined daily cost to the Libyan economy is $32.5m.

"NOC prioritises the safety of staff and is currently reviewing evacuation procedures following threats to their wellbeing, and the forced shutdown of the oilfield by the armed militia claiming attachment to the local Petroleum Facilities Guard (PFG)," NOC added.

"NOC will not take part in negotiations with the militia or is willing to compromise following their decision to revert to violence, insulting language, and theft."

“The presence of this group is a real threat to the field and to the future of our country” said NOC chairman Mustafa Sanalla.

“I want to be clear, this militia has to leave the field immediately. We stand wholeheartedly with the people of the south and understand their concerns."