The United Nations has called on forces loyal to Libya's internationally recognised government and a rival administration to commit to a humanitarian truce by midnight on Friday.

Forces loyal to Libyan strongman Khalifa Haftar said they launched air strikes early Tuesday against an airbase in third city Misrata held by government loyalists.

A Libyan airliner has narrowly escaped being hit by incoming fire as it landed at war-torn capital Tripoli's sole functioning airport, aviation officials said.

Libya's Government of National Accord has protested at what it said were "untruths" in UN envoy Ghassan Salame's latest report on the conflict in the North African country.

Fayed al-Sarraj, head of the UN-recognised GNA which is based in Tripoli, summoned Salame on Wednesday "to deliver a protest note over untruths" in his report to the United Nations Security Council, it said.

Forces loyal to Libya's UN-recognised government said they fought off a "major" attack on the capital Tripoli led by strongman Khalifa Haftar that left casualties on both sides.

Libya's internationally recognised government on Thursday demanded urgent answers after Paris conceded French missiles were found at a base used by strongman Khalifa Haftar whose forces are fighting to take over the capital Tripoli.

They are trapped in squalid detention centers on Libya's front lines. They wash up on the banks of the Rio Grande. They sink without a trace — in the Mediterranean, in the Pacific or in waterways they can't even name. A handful fall out of airplanes' landing gear.

As their choices narrow on land and at sea, migrants are often seen as a political headache in the countries they hope to reach and ignored in the countries they flee. Most live in limbo, but recent tragedies have focused attention on the risks they face and the political constraints at the root of them.

International condemnation mounted on Wednesday after more than 40 migrants were killed in an air strike on a detention centre in Libya that the U.N. said could constitute a war crime.

Six Turkish sailors held by forces led by Libyan strongman Khalifa Haftar have been freed, a Turkish foreign ministry official said on Monday.

Strongman Khalifa Haftar has threatened to attack Turkish interests in Libya after suffering a serious setback in his push to take the capital Tripoli, accusing Ankara of backing his rivals. 

Anti-Haftar forces supporting Libya's internationally recognised government announced Wednesday they had retaken the strategic town of Gharyan in a surprise attack, seizing the main supply base for Haftar's months-long offensive.