TRIPOLI, Dec. 25 (Xinhua) -- Libya's National Oil Corporation (NOC) on Monday opened three major oil ports in the east after four days of closure due to bad weather conditions.

"Foreign tankers entered the ports to load shipments delayed due to bad weather during the past few days," an official with the corporation told Xinhua.

"The closure was due to natural reasons, which delayed exports of crude oil and caused losses estimated at tens of millions of U.S. dollars," the official added.

Poor weather conditions in the oil crescent region of eastern Libya on Thursday led to temporary closure of three major oil ports.

The three ports are Brega, Zouitina and Sidra. They transport more than half of Libya's crude oil exports, said the official.

Libya has witnessed the strongest thunderstorms in many years, which affect government operations and traffic in most parts of the country.