Egypt and several Western states urged their nationals to leave Libya amid spiralling violence after two weeks of fighting left 97 people dead and a warning by state-owned National Oil Corp of a major disaster after a fuel tank was hit.
Washington evacuated its embassy staff on Saturday, with Secretary of State John Kerry warning the mission had faced a "real risk" from fierce fighting between armed groups for control of Tripoli's international airport.
Another 38 people, mostly soldiers, were killed in 24 hours of fighting between the army and Islamists in the eastern city of Benghazi, military and medical officials said on Sunday, in a further sign of the chaos plaguing the North African nation.
The Tripoli clashes, the most violent since the overthrow of dictator Moamer Kadhafi in 2011, started with an assault on the airport by a coalition of groups, mainly Islamists, which has since been backed by fighters from third city Misrata.
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 on Sunday the violence had killed 97 people, a toll based on casualty reports from eight public hospitals in the capital city and its suburbs.
More than 400 people were wounded.
Fighting was still raging, with explosions heard from early morning as militiamen battled around the airport.
State-owned National Oil Corp late Sunday warned of a major environmental and humanitarian catastrophe in the capital after a tank containing six million litres of fuel was hit by rocket fire in southern Tripoli and caught fire.
The tanks on the road leading to the airport hold a total of more than 90 million litres of fuel.
"There is a risk of a huge explosion which would cause damages in an area of between three and five kilometres," NOC spokesman Mohamed Al-Hrari told private Al-Nabaa television.
The gas and oil ministry asked residents in the area on Facebook to leave immediately for security reasons.
Egypt's foreign ministry said a rocket hit a house in Tripoli on Saturday, killing 23 people, including several Egyptians.
"There are 23 people dead after a Grad rocket fell on a house in Tripoli. Some of them are Egyptians, but we don't know how many," ministry spokesman Badr Abdelatty told AFP.
Cairo called on "all Egyptian nationals in Tripoli and Benghazi to immediately leave and save themselves from this chaotic internal fighting".
The foreign ministry said they should seek "safer areas in Libya or head to the Libya-Tunisia border".
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. There were no casualties, a spokesman for London's mission in Libya said.
"Shots were fired at our vehicles but they managed to drive on and leave the area," Bob Phillipson said.
The violence prompted Britain, France, Germany and the Netherlands to join Washington in urging their citizens to leave as soon as possible, after the US pulled out its diplomatic staff under air cover on Saturday.
Belgium, Malta, Spain and Turkey previously urged their nationals to leave.
Libya's health ministry warned that foreigners leaving 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, Tripoli said.
The airport has been closed since July 13 because of the clashes.
Libya's interim government has warned that the fighting between those vying for control of the strategic airport threatened to tear the country apart.
In second city Benghazi, another 38 people, mostly soldiers, were killed in 24 hours of intense clashes between the army and Islamists.
A military source said the fighting erupted on Saturday when Islamist groups launched an assault on the headquarters of a special forces unit near the city centre, causing casualties among forces defending their barracks.
Benghazi's main hospital said the bodies of 28 soldiers had been taken there in the past 24 hours, along with 50 wounded, while Al-Marj hospital, 100 kilometres (60 miles) to the east, spoke of two soldiers dead and 10 wounded.
A spokesman for the self-proclaimed Shura Council of Benghazi Revolutionaries, an alliance of Islamic and jihadist militia which has claimed a number of attacks on military bases in the area, said eight of its fighters were killed.
Near-daily clashes take place in Benghazi, parts of which have become strongholds for Islamist groups since Kadhafi's overthrow.