Protests are costing Libya 250,000 barrels a day of lost output--over 15% of its production capacity, the country's oil minister was quoted as saying Monday.

The disclosure comes after clashes left 31 people dead over the weekend in the eastern city of
Benghazi , underlining the security chaos in Libya .

"
Libya has been affected by sit-ins to stop production, leading to a deficit of 250,000 barrels per day," Libya 's state news agency LANA quoted Libya 's oil minister Abdel-Bari al-Arousi as saying. He said the loss was tied to protests at the oil terminals of Zueitina and Tobruk in the East of the country, and at the El Feel oil field, in the South, which is operated by Libya 's National Oil Co. and Italy 's Eni SpA (E, ENI.MI).

Earlier in the day,
Libya 's deputy oil minister Omar Shakmak said Libya 's oil production had fallen to its lowest level since January 2012. He added late Monday that crude oil production now stands at 1.115 million barrels a day because of the protests.

Libya has struggled with unrest since longtime dictator Moammar Gadhafi was deposed in the civil war in late 2011. An estimated 31 people died over the weekend in Benghazi after protesters stormed a base belonging to militias. The protesters were demanding that the militias leave their camp and submit to the full authority of Libya 's security forces.

Libya 's army chief of staff resigned Sunday following the tragedy as an elite military unit took control of a base of pro-government militias. The episode comes nine months after an attack against the U.S. consulate in the same city last year killed U.S. Ambassador Christopher Stevens and three other Americans.