The month-old battle for Tripoli has turned into a military stalemate as rival Libyan forces dig in for the long haul and foreign powers vie for influence, experts said.
Diplomatic efforts to end the conflict which erupted when strongman Khalifa Haftar launched an assault on the capital -- the seat of the internationally recognised Government of National Accord (GNA) -- have also foundered.
The April 4 offensive took many by surprise and came as UN chief Antonio Guterres visited Tripoli ahead of a subsequently cancelled UN-backed conference that was supposed to turn the page on years of conflict.
In the first days of the battle, Haftar's self-styled Libyan National Army (LNA) swiftly reached the southern outskirts of Tripoli but the GNA -- backed by powerful militias -- hit back with a counteroffensive on April 20.
Since then fighting has raged in and around Tripoli.
LNA forces are deployed in Ain Zara, a southern suburb of the capital just 12 kilometres (seven miles) from downtown Tripoli, and clashes are also taking place further south in the towns of Salaheddin and Khalat al-Ferjan.
To the west pro-GNA forces have regained some ground around the town of Al-Aziziya, but clashes continue to rock the area and elsewhere, including around the disused international airport some 30 kilometres south of Tripoli.
"The frontline is very fluid... and changes sometimes several times a day," said Jalel Harchaoui, research fellow at The Hague-based Clingendael Institute.
'Long, destructive' conflict
Libya expert Arnaud Delalande estimates the number of fighters on the ground to be around the same for both sides.
He also believes the rival forces rely on some 15 warplanes and a handful of helicopters each.
Delalande, an intelligence consultant, estimates that the LNA has 25,000 men, including 18,000 militia fighters.
The GNA can count on 18,000 members of powerful militias from the western region of Misrata, 1,500 fighters from the Tripoli Special Deterrence Forces, 1,800 from the Nawasi militia that controls the capital's east and another force of 800 men.
Harchaoui believes the even matching portends "a long military stalemate which can be destructive".
The situation is further exacerbated by divisions among foreign powers over how to respond in a country mired in conflict since the 2011 ouster of dictator Moamer Kadhafi.
A bewildering array of militias have sprouted up, and foreign powers back rival factions as they seek to gain influence in the oil-rich country.
Saudi Arabia and the United Arab Emirates back Haftar militarily along with Libya's neighbour Egypt while the GNA's allies include Turkey, Qatar and Italy, according to experts.
The GNA accuses France too of backing Haftar politically, although Paris has denied the claim.
"Haftar's foreign sponsors are known for their impatience and their taste for flexing their muscles," said Harchaoui.
"Several foreign countries are determined to back the military solution" sought by Haftar, he added, warning that the situation could get worse.
For Delalande, "only air strikes can make a difference" as to how the conflict evolves, since the lines on the ground remain so static.
Haftar's foreign friends
The GNA claims that foreign powers have been involved in air raids on neighbourhoods in southern Tripoli.
Delalande contends that local aircraft and equipment are not up to carrying out such strikes, which happen at night.
"The remains of missiles found after air strikes leave no doubt as to their origin: (they are) Chinese-made LJ-7, also known as Blue Arrow 7," said Delalande.
These air-to-surface missile can be loaded onto the Chinese-made Wing Loong 2 drone, he added.
"The United Arab Emirates has them and have deployed them at Al-Khadim air base" in eastern Libya, he said.
"The Egyptian air force have had them since October," added Delalande. And "the UAE and Egypt have backed Haftar since 2014, supplying him with planes, helicopters, armoured vehicles, weapons etc..."
Harchaoui said Egypt and the UAE "don't want to see Haftar fail" or be "defeated".
"As long as he is not defeated, his army will continue to put military pressure on the recognised government," he said, warning that the conflict "could drag on and be dirty".
On the diplomatic front, a British-led effort to get the UN Security Council to agree to demand a ceasefire ran aground after the United States withheld its support in an apparent tilt towards Haftar, while Russia has openly refused to condemn the strongman's offensive.