Several drone attacks against Libya's Zawiya refinery have been reported since Sunday.
A fire, accompanied by heavy smoke, broke out on Monday in a diesel tank oil depot at the refinery after the tank was struck, Brega Petroleum Marketing Company said in a statement.
The facility was attacked by a drone, Libya's National Oil Corporation said in a statement early Tuesday morning, adding that the plant suffered no damage or casualties.
After this attack, the company announced that it will be forced to completely halt operations at the refinery should attacks continue.
The refinery was targeted by a drone again, Saudi state-owned Al Arabiya reported on Tuesday morning.
Brega is owned by state oil firm NOC and is in charge of fuel supplies.
Zawiya refinery, the largest in the country as Ras Lanuf is out of operation, around 40 km (25 miles) west of Tripoli, has a capacity of 120,000 barrels per day. It is connected to the country's 300,000 bpd Sharara oilfield.
Firefighter brigades are working on containing the blaze, the company said.
Tank 'was directly targeted,' NOC said
The tank, with an estimated 4.5 million liters of gasoline, "was directly targeted," NOC said in a statement, declaring the extreme state of emergency in the area.
It demanded that competent authorities "immediately intervene" and launch investigations into the incident.
Unverified footage posted on the internet showed huge blazes and thick black smoke billowing in the sky in Zawiya city.
The refinery is still functioning without any suspension, two engineers working at the refinery said.
The incidents came two days after a drone crashed into an untreated naphtha tank at the Zawiya refinery early on Saturday, causing a leak that staff managed to control.