Benghazi (Libya) (AFP) - Forces loyal to Libya's UN-backed unity government launched an offensive on Sunday aimed at retaking key eastern oil ports seized last week by fighters from a rival administration.
The Tripoli-based Government of National Accord has struggled to assert its authority over the country since the GNA was formed in December last year.
Oil is Libya's key asset, and revenue from crude exports is vital if the GNA is to rebuild the economy and infrastructure of the North African nation, ravaged by violence since the 2011 uprising.
The revolt that ousted and killed dictator Moamer Kadhafi plunged Libya into chaos, with militias, jihadists and rival administrations vying for control of its oil wealth and territory.
Last week, forces led by controversial military strongman Khalifa Haftar seized the ports of Ras Lanuf, Al-Sidra, Zuwaytina and Brega in the so-called "oil crescent" along the coast.
They later handed them over to the National Oil Corporation.
The NOC says it is loyal to the GNA, but also to the internationally recognised parliament based in the east which supports Haftar's forces and has refused to give the GNA a vote of confidence.
"The Petroleum Facilities Guard (PFG) launched an offensive this morning and (our forces) are fighting them in Ras Lanuf," said Mohamad Ibset, a spokesman for Haftar's forces.
The PFG, which is loyal to the government in Tripoli, said it had launched counterattacks on two of the oil ports.
- 'Unite to rebuild' -
"We attacked Al-Sidra and Ras Lanuf, and Haftar's forces are trying to hit us with their warplanes," spokesman Ali al-Hassi told AFP.
Muftah al-Muqarief, who heads oil guards loyal to Haftar, said the assault on the ports was launched from the west by "militias backed by outlaws".
"We repelled the attack and we are chasing them in the region," he said, adding that "some" assailants had been captured.
There was no independent confirmation from the oil crescent region of the fighting and the situation on the ground.
The British ambassador to Libya, Peter Millet, took to Twitter to urge restraint.
"Further fighting around oil crescent installations is bad for future of Libya's economy. Better to resolve differences by dialogue," he wrote.
"Libyans should unite to rebuild their country not destroy it," he added.
The loss of the ports was a blow to the GNA which set up base in the capital in March, months after it was created as the result of a UN-backed power-sharing agreement.
Haftar, who sees himself as Libya's saviour after driving jihadists out of most of the country's second city Benghazi, is the most powerful backer of the rival administration in the east.
Days after the ports fell under his control, the east-based parliament promoted Haftar to field marshal from his previous rank of general.
The administration that backs him announced on Wednesday that it would hand control of exports from the four ports to the NOC, albeit under the supervision of Haftar's forces.
NOC chairman Mustafa Sanalla said on Thursday that exports would resume immediately from two of the ports, including Ras Lanuf.
The US special envoy for Libya, Jonathan Winer, warned that resumed oil exports would be acceptable only if the proceeds were paid into the Libyan central bank in Tripoli.
"If oil were to be diverted... the US will seek to enforce UN Security Council resolutions," Winer told AFP in an interview on Wednesday.
The fighting between the forces of the rival administrations is the latest escalation of the turmoil that has gripped Libya since Kadhafi was toppled.
The GNA is the centrepiece of UN efforts to restore stability and forge a central authority capable of tackling the twin scourges of a significant Islamic State group presence and rampant people trafficking across the Mediterranean to Europe.