World powers are counting on a fledgling Government of National Unity (GNA) to assert its authority and put an end to the chaos in the wake of the 2011 revolt that ousted longtime leader Moamer Kadhafi.
Here are some questions and answers:
Who governs Libya?
The political scene is split into two camps.
The UN-backed GNA, formed in late March and based in Tripoli, has gained the support of key armed militias in western Libya, a region which it now mostly controls.
But it faces resistance from a government which previously had international recognition. Based in eastern Libya, it refuses to hand over power before the GNA wins a confidence vote in parliament, a move that has been repeatedly postponed.
Who are main military forces?
GNA armed forces, made up of powerful local militias and units of Libya's divided army, are based in the western town of Misrata.
Equipped with tanks and warplanes, they control several airports.
The international community, at a meeting in Vienna on Monday, agreed to arm the GNA to fight the Islamic State jihadist group, in an easing of an embargo imposed to halt the Libyan conflict of 2011.
The new government welcomed the decision and said it wants warplanes and helicopters to fight the jihadists.
Libya's rival authorities control the east, also with local militias on the ground and army units under the command of General Khalifa Haftar.
Their armed forces -- equipped with warplanes, tanks and armoured vehicles -- are concentrated in around Libya's second city of Benghazi.
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For the past two years, they have appealed for a lifting of the arms embargo to fight "terrorist groups", with IS also in its sights.
Libya has two other armed forces: the Cyrenaica Force and Revolutionary Shura Council of Derna.
The Cyrenaica Force is a local tribal coalition which controls oil terminals in eastern Libya and has sworn allegiance to the GNA.
The Revolutionary Shura Council is a mix of militias including Islamists that now controls Derna, a city 1,100 kilometres (650 miles) east of Tripoli. It opposes Haftar but has yet to announce a stand on the GNA.
The different forces are fighting separately against IS, which has taken advantage of the divisions to implant itself in post-Kadhafi Libya, mainly in the east.
Where is IS?
In June 2015, IS seized control of the slain dictator's coastal hometown of Sirte, half-way between Tripoli and Benghazi.
It has built up a force of an estimated 5,000 fighters, mostly non-Libyans, and has spread to the east and west of Sirte, just 300 kilometres across the Mediterranean from Europe.
IS holds sectors around the city of Derna, inside Benghazi and small towns and villages to the east of Sirte, up to the fringes of eastern oil terminals, and has made inroads in a strategic region linking eastern and western Libya.
It has failed to recruit a large number of Libyans, "in a generally conservative society but one that has never been extremist", in the words of a security official in Tripoli.
Impact on economy?
Despite holding the richest oil reserves in Africa, Libya's exports have plunged from pre-revolution levels of almost 1.5 million barrels per day to barely 300,000 bpd.
While insecurity makes tax collection almost impossible, prices of goods in Libya have shot up since the end of 2015 mainly because of the rising US dollar on the foreign exchange market.
Situation on borders?
Libya, apart from its 1,700-kilometre coastline, has land borders with Niger, Chad, Sudan, Algeria, Tunisia and Egypt, making it a prime transit route for migrants seeking to reach Europe and ultra-vulnerable to people traffickers.