Libya was expected to call in firefighting planes Monday to douse a huge blaze sparked by clashes near Tripoli's airport, as foreigners were urged to quit the increasingly lawless country.
Officials said firefighters on the ground had failed to put out the oil tank blaze near Tripoli airport and that an air intervention was the only option to avert a catastrophe.
State-owned National Oil Corp has warned of a humanitarian and environmental catastrophe after the tank containing six million litres of fuel was set ablaze by rocket fire late on Sunday.
Residents have been urged to evacuate areas within five kilometres (three miles) of the blaze on the airport road, where fuel reserves of more than 90 million litres are stored.
"Firefighters have been trying for hours to put out the blaze but to no avail. Their water reserves finally ran out and they've had to leave," said NOC spokesman Mohamed al-Hrari.
He said the only option left was "intervention by air", as the government said several countries had offered to send fire-fighting aircraft in response to an appeal for international aid.
The Tripoli clashes, the most violent since a 2011 armed revolt which overthrew longtime dictator Moamer Kadhafi, started with a July 13 assault on the airport by armed groups, mainly Islamists.
Fighting was still raging early on Monday, with explosions heard from central Tripoli.
The attackers are battling to flush out fellow former rebels from the hill town of Zintan, southwest of Tripoli, who have controlled the airport for the past three years.
The health ministry said Sunday that the violence which has kept the airport closed for more than two weeks had killed 97 people and left more than 400 others injured.
Egypt and several Western states urged their nationals to leave Libya amid the spiralling violence which has also hit the eastern city of Benghazi, birthplace of the 2011 revolution.
Fighting over the weekend between army special forces and Islamists in Benghazi killed 28 people, mostly soldiers, military and medical officials said.
Washington evacuated its embassy staff on Saturday, with Secretary of State John Kerry warning the mission had faced a "real risk" from the fighting for control of Tripoli airport.
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- Foreigners urged to quit -
Egypt's foreign ministry, meanwhile, said a rocket hit a house in Tripoli on Saturday, killing 23 people, including several Egyptians.
Cairo urged "all Egyptian nationals in both Tripoli and Benghazi to immediately leave and save themselves from this chaotic internal fighting".
They should seek "safer areas in Libya or head to the Libya-Tunisia border", it said.
There were an estimated 1.5 million Egyptians in Libya before Kadhafi's ouster. About two-thirds left during the war but many returned in 2012.
Also on Sunday, a British embassy convoy was fired on in a suspected attempted carjacking in western Tripoli, without any casualties reported.
The violence has led Britain, France, Germany and the Netherlands to join Washington in urging their citizens to leave as soon as possible.
Libya's health ministry, meanwhile, warned that an exodus could cause a shortage of health workers, particularly since the Philippines ordered the departure of its citizens, 3,000 of whom were doctors and nurses in Libya.
The latest fighting in Benghazi erupted on Saturday when Islamist groups launched an assault on the headquarters of a special forces unit near the city centre, military officials said.
Near-daily clashes take place in Benghazi, parts of which have become strongholds for Islamist groups since Kadhafi's overthrow.