MELLITAH, Libya, March 7 (Reuters) - In a country that desperately needs to keep oil and gas exports flowing to rebuild after civil war, paying 15,000 men with guns to guard Libya's energy industry sounded like a good idea. Last Saturday it backfired.
The precise details of who shot at whom are murky and will probably remain so, but when the shooting stopped at the Mellitah gas complex 100 km (60 miles) west of the capital Tripoli, at least one person was dead and seven injured.
Gas exports to Italy through a pipe carrying up to 8 billion cubic metres per year - equivalent to 10 percent of Italian consumption - have been cut off and have yet to be restarted.
Locals say the fighting involved men from the area and some outsiders from another town, members of the Petroleum Facilities Guard (PFG), a heavily-armed but barely-trained force recruited to defend oil and gas plants.
Since the gun battle, the plant, jointly owned by Libya's state oil company and Italy's ENI,, is under the control of the special unit and the military. ENI withdrew its foreign staff and the plant was shut down.
It is now surrounded by tanks and pickup trucks mounted with anti-aircraft guns. Dozens of security personnel stood at sandbagged checkpoints nearby.
"There are issues between the two sides - some even say this belongs to them, others say it doesn't," explained a member of the special force now guarding the plant.
"But the army has now taken over and a settlement is being reached. We are all revolutionaries and we are all brothers."
The violence, and the threat to Libya's exports, show the problems the country has faced taming its various heavily armed militia groups since the civil war that overthrew Muammar Gaddafi in 2011.
Across the country, groups of fighters have refused to disband. Many have been given official permission to continue to carry guns and are paid by the central authorities for guard duties, but few have proper training and lines of command are murky.
The Petroleum Facilities Guard force operates under the official remit of the Defence Ministry, but only about 2,000 of its 15,000 members have training from the military.
"The central government is struggling to exert control over oil facilities and the result is interruptions to Libyan production," Richard Mallison, chief policy analyst at Energy Aspects, a consultancy, said. "It seems clear that relying on militia will not provide reliable security at oil and gas facilities given the disputes between different groups."
Protests have hurt Libya's oil output, which had quickly returned almost to pre-war levels of 1.6 million barrels per day (bpd) after the country's uprising.
"Our view is that Libyan production is going to struggle to exceed 1.3 million bpd while the current problems continue," Mallison said.
Although turf battles between militia groups have been common since Gaddafi's fall, until Saturday oil and gas installations had largely been spared.
In the past year, cracks have begun to show in Libya's speedy oil recovery, but the main issues were labour unrest or protests by local communities with social demands, rather than full-fledged militia gun battles.
Protesters forced the closure of three major oil terminals last July. In December, protesters demanding jobs shut down the eastern Zueitina oil terminal. Wounded rebels demanding compensation closed western Libya's main oil refinery twice.
In some of those cases, guards took little action to stop disruption. But Saturday seems to have been the first time that fighting involved the guards themselves.
Now, questions are being asked about the oil guards force itself. It is made up of rebel fighters absorbed as "brigades" - bands, usually from the same town, who fought together in the war and whose loyalties often lie with their field commanders.
"There are worries among oil workers that they may be poorly disciplined," a Libyan oil industry source acknowledged.
The PFG force is divided into five branches across Libya. The west to the southern border with Niger is mainly guarded by former rebel fighters of Zintan, a straggling western mountain town of 35,000 people, which prides itself on a history of martial prowess far beyond its modest size and prosperity.
As part of the PFG force, Zintan fighters have guarded major oilfields like Eni's El Feel and Repsol's Sharara in the southwest as well as Mellitah on the Mediterranean coast.
More Zintanis have been deployed to guard oil and gas installations and the border since January's attack by militants on a gas plant in neighbouring Algeria. But locals in towns where the complexes are located sometimes resent the outsiders.
Saturday's fighting at Mellitah erupted from a quarrel that had dragged in the Zintani fighters and armed men from the nearby town of Zuwara. There, residents said locals were unhappy with the behaviour of some Zintanis and tried to evict them.
Two bouts of fighting followed before state armed forces took control.
"The majority of people didn't like them there but nothing was done about it," said Yussef al-Hassairi, a member of the Zuwara local council, describing attitudes towards the Zintanis. "In future, those guarding Mellitah should mainly be from Zuwara and nearby towns. There is local agreement on this."
Mokhtar al-Akhdar of the Zintan military council said it was important that forces guarding oil and gas bases were controlled by the central authorities.
"The army and defence ministry should take charge of guarding vital installations," he said. "There shouldn't be anymore militias."
A PFG spokesman said the future force guarding Mellitah would be mixed with men from different regional areas.
"There will be strict rules. If anyone is going to make any problems or not stick to the rules, they will be fired," Walid Hassan Mohammed, PFG director of public relations, said.
Mellitah Chairman Abdufattah Shagan said it would take days for operations at the complex to resume normally.
"The security issue is a top priority in all the country, not just the oil sector," he told Reuters. "Without security we will not be able to run any operation."
PFG members accept that they have a way to go but take pride in their work. "We need training," one said. "But we can protect the Libyan treasure".