BENGHAZI, Libya (AP) — Libya's National Oil Corporation says an armed group opposed to Libya's self-styled national army has attacked key oil port terminals "significantly" damaging at least one storage tank.

Saturday's statement by the company called on the group commanded by Ibrahim Jadhran to withdraw to prevent an "environmental disaster" and further damage to infrastructure.

NOC says the oil ports of Ras Lanuf and Es Sidr have been under attack since Thursday forcing it to announce a "force majeure" on crude oil loadings and evacuate its employees from the areas.

Jadhran's group had previously controlled the ports at Libya's oil crescent and blockaded them, costing oil-rich Libya billions of dollars, before losing them to national army forces in 2016.

Libya has descended into chaos following a 2011 uprising that toppled a longtime ruler.