Three oil tankers were hit and burned Friday in Libya's largest oil port in the oil crescent, after an attack by militias of Libya Dawn with a rocket-propelled grenade, according to a military official.

"On Friday, two oil tanks were burned after another tank was burned on Thursday by the rocket-propelled grenade fired by militants of Libya Dawn from a boat in the sea toward the harbor." Said Ali Al-Hassi, spokesman of the army forces in the oil crescent area.

Mohamed Al-Hrari, spokesman for the National Oil Corporation, confirmed the "incident," demanding to "neutralize the oil institutions from conflict."

Witnesses told Xinhua the fire and smoke completely cover with areas of Sidra and Ras Lanuf (130 kilometers east of Sirte), threatening to cause environmental disaster in the event of failure to control the fire.

On Thursday, at least 22 soldiers were killed in the city of Sirte in an attack by the militias against an army battalion. Also, fire broke out in an oil tank in the area after it was hit with a shell.

Libya Dawn militias launched earlier last week a military operation to take control of the oil crescent area called "Sunrise Operation to liberate oil ports and fields", claiming they have been mandated by the expired General National Congress.

However, the operation's leader Tariq Shnena was killed in an air raid after the attack.

Oil crescent area includes a group of cities between the cities of Benghazi and Sirte (500 km east of the capital Tripoli). It contains the largest oil reserves in the country, in addition to the ports of Sidra, Ras Lanuf, and Brega, the country's largest ones.

Since December 13, the battles have slashed Libya's oil production from 800,000 barrels per day to about 200,000 barrels, causing a loss of billions of U.S. dollars to its general budget, according to Libyan officials.