Forces opposed to Libya's unity government have seized a fourth oil port, Brega, completing their takeover of vital installations in the North African country's "oil crescent", according to military sources.
The UN-backed Government of National Accord (GNA) based in Tripoli is struggling to assert its authority and has faced staunch resistance from a rival administration based in Libya's remote east.
Forces loyal to Khalifa Haftar, a renegade general, on Sunday launched an offensive on Libya's "oil crescent" along the northern coast.
READ MORE: UK parliament report criticises Libya intervention
Haftar, 73, who sees himself as Libya's saviour after battling conservative armed groups out of most of second city Benghazi in the east, backs the Bayda-based parliament which has refused to grant the GNA a vote of confidence.
His forces fought off guards to gain control of the oil terminals at Ras Lanuf, Al-Sidra and Zuwaytania, and they finally secured Brega unopposed on Tuesday.
"We have taken control of the Brega port completely and without any fighting," said Colonel Muftah al-Muqarief, who heads oil guards loyal to Haftar.
"The entire oil crescent region is now under our control," Muqarief told AFP news agency.
Brega was taken largely thanks to "mediation involving residents and town elders", he said.
The Brega takeover came just hours after the United States and its major European allies - which back the GNA - condemned Haftar's offensive.
The US, France, Germany, Italy, Spain and Britain said the UN-brokered government based in the capital, Tripoli, is the "sole steward of these resources", adding that "Libya's oil belongs to the Libyan people".
"We also call on all forces to avoid any action that could damage Libya's energy infrastructure or further disrupt its exports," said the joint statement, issued late on Monday.
|Haftar's forces have driven conservative armed groups out of most of Benghazi [Reuters]
It also warned against "illicit oil exports".
The statement echoed remarks by Martin Kobler, the UN special envoy, on Monday.
"I call for the respect of UN Security Council Resolution 2259, which recognises the Government of National Accord ... as the sole executive authority in Libya," Kobler said.
Oil is Libya's main natural resource, with reserves estimated at 48 billion barrels, the largest in Africa, but production has dropped since 2011 when the country plunged into turmoil.
On Sunday, Haftar's forces took Al-Sidra and Ras Lanuf ports before attacking Zuwaytina to the east.
The "oil crescent" lies between Benghazi and Gaddafi's hometown of Sirte, where pro-GNA forces have been battling the Islamic State of Iraq and the Levant (ISIL) group since May.
It was the first time Haftar's forces and fighters loyal to the GNA clashed directly since the unity government started working in Tripoli in March.
Kobler said oil installations must remain under the authority of the GNA's presidential council and stressed that Resolution 2259 "contains a clear prohibition on illicit oil exports".
The GNA called on loyalist forces to "protect and defend" the ports against what it called a "flagrant aggression" against Libya's sovereignty.
For his part, the head of the rival government, Abdullah al-Thani, said from Bayda that his administration "will work on the oil ports resuming work as soon as possible so as to guarantee all Libyans a decent life".
Aguila Saleh, speaker of the Bayda-based parliament, said Haftar's forces would withdraw and hand over the ports to the National Oil Corporation (NOC) to resume oil exports.
He said Haftar's move was by "popular demand" and was authorised by Libya's official institutions.
The Jedran factor
Saleh said Haftar's forces "liberated the fields and the terminals from the occupiers and those hindering exports", referring to Ibrahim Jedran, who commands a force known as Petroleum Facilities Guards.
Jedran's fighters seized the oil terminals more than two years ago and have tried to export illegally in the past.
It is now allied with the GNA, and Kobler brokered a deal with Jedran in July to resume exports.
The NOC is split into two rival branches, one allied to the GNA and the other to the administration that Haftar supports.
On Tuesday, the NOC branch allied with Haftar said it would immediately start working to resume crude exports from ports seized by his forces.
"Our technical teams already started assessing what needs to be done to lift force majeure and restart exports as soon as possible," Mustafa Sanalla, NOC chairman, said in a statement.
The battle for control of Libya's oil assets has renewed fears of a civil war in the country, which plunged into chaos after the 2011 uprising that toppled and killed longtime leader Muammar Gaddafi.