Forces loyal to Libyan military strongman Khalifa Haftar blocked oil exports from the war-ravaged country's main ports Saturday, raising the stakes on the eve of an international summit aimed at bringing peace to the North African nation.

The move to cripple the country's main income source was a protest against Turkey's decision to send troops to shore up Haftar's rival, the head of Tripoli's UN-recognised government Fayez al-Sarraj.

It comes ahead of Sunday's conference in Berlin that will see the United Nations try to extract a pledge from world leaders to stop meddling in the Libyan conflict -- be it through supplying troops, weapons or financing.

"All foreign interference can provide some aspirin effect in the short term, but Libya needs all foreign interference to stop," UN Libya envoy Ghassan Salame told AFP in an interview.

But Sarraj issued a call for international "protection troops" if Haftar keeps up his offensive.

Libya has been torn by fighting between rival armed factions since a 2011 NATO-backed uprising killed dictator Moamer Kadhafi and toppled his regime Libya has been torn by fighting between rival armed factions since a 2011 NATO-backed uprising killed dictator Moamer Kadhafi and toppled his regime Photo: AFP / Mahmud TURKIA

"Such a protection force must operate under the auspices of the United Nations. Experts will have to advise who should participate, such as the EU or the African Union or the Arab League", he told the Die Welt newspaper on Sunday.

The presidents of Russia, Turkey and France as well as US Secretary of State Mike Pompeo are to join the Sunday talks, held under the auspices of the UN.

Haftar and Sarraj are also expected, German Foreign Minister Heiko Maas confirmed Saturday, ahead of the first gathering of such scale on the conflict since 2018.

After months of combat, which has killed more than 2,000 people, a ceasefire took effect on January 12 backed by both Ankara and Moscow, which is accused of supporting Haftar.

But Saturday's blockade raised fears over the conflict.

The disruption to oil exports is expected to more than halve the country's daily crude production, to 500,000 barrels from 1.3 million barrels, translating to losses of $55 million a day, warned Libya's National Oil Company.

Haftar's forces launched an assault in April on Sarraj's troops in Tripoli Haftar's forces launched an assault in April on Sarraj's troops in Tripoli Photo: AFP / ARIS MESSINIS

"Our line at the UN is clear. Don't play with petrol because it's the livelihood of the Libyans," warned Salame just hours before the blockade.

Jalel Harchaoui, an expert at the Hague-based Institute Clingendael, said the petrol blockade was part of "the logic of blackmail".

"It can work, but there's also a risk that Washington will react badly" he said. Washington was deeply opposed to any move that could drive up crude prices, he added.

The oil-rich North African country has been torn by fighting between rival armed factions since a 2011 NATO-backed uprising killed dictator Moamer Kadhafi and toppled his regime.

More recently, Haftar's forces launched an assault in April on Sarraj's troops in Tripoli.

Map of forces involved in the fighting in Libya, as of December 31, 2019 Map of forces involved in the fighting in Libya, as of December 31, 2019 Photo: AFP / Thomas SAINT-CRICQ

Although Sarraj's government is recognised by the UN, some powerful players have broken away to stand behind Haftar -- turning a domestic conflict into what is essentially a proxy war with international powers jostling to secure their own interests.

Alarm grew internationally when Ankara ordered in troops early January to help shore up Sarraj. Russia has denied accusations it provided weapons, financing and mercenaries to Haftar.

"We must end this vicious cycle of Libyans calling for the help of foreign powers. Their intervention deepens the divisions among the Libyans," said Salame.

The place of international players should be to "help Libyans develop themselves", he added.

The UN envoy said Sunday's meeting will also seek to "consolidate" the shaky ceasefire.

"Today we only have a truce. We want to transform it into a real ceasefire with monitoring, separation (of rival camps), repositioning of heavy weapons" outside urban zones, he said.

Although the UN has tried repeatedly to broker peace, talks have repeatedly collapsed.

On the eve of the Berlin talks, Turkish President Recep Tayyip Erdogan warned Europe to stand united behind Sarraj's government, as Tripoli's fall could leave "fertile ground" for jihadist groups like IS or Al-Qaeda "to get back on their feet".

Erdogan also played up Europe's fears of a repeat of the 2015 refugee crisis in his commentary for Politico news website, saying further unrest could prompt a new wave of migrants to head for the continent.

Accusing France in particular of siding with Haftar, Erdogan said leaving Libya to the commander would be a "mistake of historic proportions".

France has denied it is backing Haftar.

The European Union is watching the escalating strife on its doorstep with growing alarm, as it counts on Libya as a gatekeeper deterring migrants from crossing the Mediterranean.

On Sunday Sarraj said the bloc had not been proactive enough on Libya.

"Unfortunately the role of the EU so far has been very modest... even though some EU countries have a special relationship with Libya, we are neighbours and have many interests in common," he said.