The battle for Libya's capital intensified as the UN Security Council prepared to meet Wednesday to discuss the crisis gripping the North African country, where armed rivals are locked in a deadly power struggle.
The closed-door talks in New York come a day after the United Nations postponed a Libyan national conference aimed at drawing up an election roadmap because of fighting raging on Tripoli's doorstep.
Libya has been riven by divisions since the NATO-backed overthrow of dictator Moamer Kadhafi in 2011, with various armed groups and two parallel governments vying for territory and oil wealth.
Heavy arms fire was heard during much of the night in the Ain Zara district on the southeastern outskirts of Tripoli as strongman Khalifa Haftar's forces pressed an assault aimed at taking the capital from the UN-backed Government of National Accord (GNA).
"The clashes have intensified. We're afraid to leave the house," a resident told AFP by telephone from the area, where roads were reported to have been blocked, hindering people's efforts to flee.
The violence has already displaced thousands and left several dozen people dead.
The UN warned that nearly half a million children in Tripoli were "at immediate risk".
Haftar's self-styled Libyan National Army (LNA), which controls swathes of the country's east, said it had seized a barracks in the Aziziya area around 50 kilometres (31 miles) south of Tripoli after "ferocious clashes".
It said several fighters loyal to the UN-backed government had been detained and their weapons seized.
The internationally recognised government carried out several air raids against LNA positions south of Tripoli, and also hit supply lines in central Libya, GNA spokesman Colonel Mohamed Gnounou said Tuesday.
Haftar's forces appear to be advancing on two fronts, from the south and southeast of Tripoli, while coastal roads to the east and west of the city are defended by fighters loyal to the GNA.
- 'Spare civilians' -
Hafter has defied international calls, including from the UN Security Council and the United States, to halt the surprise offensive launched on Thursday.
The UN's high commissioner for refugees, Filippo Grandi, called for the warring parties to "spare civilians, including refugees and migrants trapped in the country".
The UN children's agency (UNICEF) urged all parties "to refrain from committing grave violations" against children, including the recruitment of child soldiers.
"Nearly half a million children in Tripoli and tens of thousands more in the western areas are at a direct risk due to the intensification of fighting," it said.
The GNA's health ministry on Monday put the death toll in the fighting at 35. Haftar's forces have said 14 of their fighters have died.
The UN said the clashes have displaced some 3,400 people.
Led by Fayez al-Sarraj, the GNA's authority is not recognised by a parallel administration in the east of the country, which is allied with Haftar.
LNA spokesman Ahmad al-Mesmari accused the unity government of "allying itself with Islamist militias" from the city of Misrata 200 kilometres (120 miles) east of the capital.
- Peace efforts stalled -
International efforts to end the Libyan conflict have repeatedly failed.
Rival leaders agreed last year to hold elections before December 10, 2018 under a French plan, but that vote never materialised.
The national conference, which had been scheduled for April 14-16 in the central city of Ghadames, aimed to fix dates for legislative and presidential elections, and work towards a new constitution.
UN envoy Ghassan Salame, announcing its postponement, said: "We cannot ask people to take part in the conference during gunfire and air strikes."
He expressed hope the meeting would take place "as soon as possible".
Haftar, whose key allies are the United Arab Emirates, Egypt, Saudi Arabia and Russia, is a former Kadhafi military chief who has emerged as a major player in Libya's political struggle.
His offensive threatens to plunge the country into a full-blown civil war and has thrown into sharp relief the divisions between world powers over how to end the chaos that has riven Libya since 2011.