A warplane attacked Tripoli's only functioning airport on Monday as eastern forces advancing on the Libyan capital disregarded international appeals for a truce in the latest of a cycle of warfare since Muammar Gaddafi's fall in 2011.
Casualties were mounting in fighting that also threatens to disrupt oil supplies, fuel migration to Europe and wreck U.N. plans for an election to end rivalries between parallel administrations in the country's east and west.
The eastern Libyan National Army (LNA) forces of Khalifa Haftar - a former general in Gaddafi's army - said 19 of its soldiers died in recent days as they closed in on the internationally recognised government in Tripoli.
A spokesman for the Tripoli-based Health Ministry said fighting in the south of the capital had killed at least 25 people, including fighters and civilians, and wounded 80.
Mitiga airport, in an eastern suburb, was bombed and closed, authorities said. That left Misrata airport, 200 km (125 miles) to the east down the coast, as the closest option for Tripoli residents.
Haftar's LNA, which backs the eastern administration in Benghazi, took the oil-rich south of Libya earlier this year before advancing fast through largely unpopulated desert regions toward Tripoli.
Seizing the capital, however, is a much bigger challenge. The LNA has conducted air strikes on the south of the city as it seeks to advance along a road from a disused former international airport.
Witnesses said on Monday afternoon that the LNA had lost control of the old airport and withdrawn from positions on the airport road. Forces allied to the Tripoli administration were seen inside the airport, while clashes with the eastern forces were raging south of the airport, a Reuters reporter at the scene and residents said.
On Sunday evening, LNA forces had moved up from the airport coming as close as 11 km (seven miles) from the city center before retreating, residents said.
MACHINE GUNS ON PICKUPS
The government of Prime Minister Fayez al-Serraj, 59, is seeking to block the LNA with the help of allied armed groups who have rushed to Tripoli from Misrata in pickup trucks fitted with machine guns.
A Reuters correspondent in the city centre could hear gunfire in the distance southwards.
Serraj has run Tripoli since 2016 as part of a U.N.-brokered deal boycotted by Haftar. His Tripoli government has reported 11 deaths in the last few days, without saying on which side.
The United Nations said 2,800 people had been displaced by the clashes and many more could flee, though some were trapped.
"The United Nations continues to call for a temporary humanitarian truce to allow for the provision of emergency services and the voluntary passage of civilians, including those wounded, from areas of conflict," it said in a statement.
U.N. envoy Ghassan Salame met Serraj in his office in Tripoli on Monday to discuss "this critical and difficult juncture", the U.N.'s Libya mission said.
The violence has jeopardised a U.N. plan for an April 14-16 conference to plan elections and end anarchy that has prevailed since the Western-backed toppling of Gaddafi.
As well as the United Nations, the European Union, United States and G7 bloc have all urged a ceasefire, a halt to Haftar's advance and return to negotiations. Haftar casts himself as a foe of extremism.
MIGRANTS AND MILITANTS
The LNA says it has 85,000 men, but this includes soldiers paid by the central government that it hopes to inherit. Its elite Saiqa (Lightning) force, numbers some 3,500, while Haftar's sons also have well-equipped troops, LNA sources say.
Since NATO-backed rebels ousted Gaddafi, Libya has been a transit point for hundreds of thousands of migrants trekking across the Sahara in hope of reaching Europe across the sea.
Islamic State staged some high profile attacks in Tripoli last year, but the militant group has largely retreated to the desert of southern Libya since the loss of its former stronghold in Sirte in late 2016.
France, which has close links to Haftar, said it had no prior warning of his push for Tripoli, a diplomatic source said.
France established close relations with Haftar under the Socialist government of former President Francois Hollande and his defence minister, Jean-Yves Le Drian.
When President Emmanuel Macron named Le Drian his foreign minister, Paris increased support for Haftar, which see him as a bulwark against Islamists and have supported him militarily, according to U.N. reports.
France's stance has created tensions with Italy, which has sought a leading role to end the turmoil in its former colony.
*This story was edited by Ahram Online.