Two oil storage tanks remain on fire at Libya's Es Sider oil port while two others have collapsed almost a week after clashes there sparked the blaze, a spokesman for state National Oil Corp (NOC) said on Tuesday.
Fires at two other storage tanks at Libya's biggest oil port had been extinguished but the damage was unclear, NOC spokesman Mohamed El Harari said.
An industry source said at least 1.2 million barrels of oil had been destroyed by the fire which broke out after clashes reported on Dec. 25 between armed factions allied to Libya's internationally recognized government and a group called Libya Dawn which is vying for control of the country.
Libya's two largest ports, Es Sider and Ras Lanuf, have stopped since a force loyal to a rival government in Tripoli tried seizing them from forces allied to the recognized Prime Minister Abdullah al-Thinni.
Thinni has been forced to work out of the east since a rival group called Libya Dawn seized Tripoli in August, setting up its own government and parliament unrecognized by world powers.
Es Sider is fed from fields run by Waha Oil Co, a joint-venture between Libya's National Oil Corp with U.S. companies Hess, Marathon and ConocoPhillips.
Without the two ports previously accounting for around 300,000 bpd, Libya's total output was in the range of the 380,000 bpd reported on Sunday, Harari said.
The ports of Zawiya and Mellitah in the west of the country have also halted oil exports as the conflict has shut down the connecting fields of El Sharara and El Feel. Only the ports of Hariga and Brega in the east and two offshore fields are still working.
(Writing by Ulf Laessing; editing by Jason Neely and Louise Heavens)