Flames and smoke on Monday billow from an oil depot containing 6 million liters of fuel which was set ablaze by rocket fire late on Sunday near Tripoli airport. State-owned National Oil Corp has warned of a humanitarian and environmental catastrophe. Photo: AFP

The Libyan government said a second fuel depot caught fire Monday in Tripoli, in a "very dangerous" development following a huge oil tank blaze triggered by clashes around the capital's airport.

The authorities rushed to evacuate people from their homes in the area along the road to the airport, where rival militias have been fighting each other for the past two weeks.

The first depot, which contains 6 million liters of fuel, is about 10 kilometers from the Libyan capital. It caught fire on Sunday when it was hit by rockets fired by the combatants, who are jostling for control of the airport.

The depots, run by state-owned National Oil Corp (NOC), contain more than 90 million liters of fuel and the fire is "out of control."

NOC spokesman Mohamed al-Hrari said that firefighters have run out of water reserves and the only option left was "intervention by air," as the government said several countries had offered to send firefighting aircraft in response to an appeal for international aid.

Fighting in the area has claimed the lives of 97 people and left more than 400 injured, according to the latest figures released by the health ministry.

Several countries, including Britain, France, Germany and Egypt have all warned their citizens not to travel to Libya, while the US evacuated its embassy over the weekend.

Other countries, among them the Netherlands, Belgium, Spain and Turkey have advised their nationals to leave the country immediately.

The exodus of foreign workers will further hit the strife-torn country, while the health ministry warned of a shortage of medical staff after the Philippines announced it was withdrawing its citizens, including 3,000 doctors and other healthcare workers.

The Tripoli clashes, the most violent since a 2011 armed revolt which overthrew longtime dictator Muammar Gaddafi, started with a July 13 assault on the airport by armed groups, mainly Islamists.