By Lin Noueihed and Tarek Amara
DEHIBA, Tunisia (Reuters) - An empty pickup truck veers off the winding road near the Tunisian hamlet of Ouni, separated from Libya by only a few hundred meters of unmarked scrub. Three men jump out and begin to stack gallon bottles full of contraband petrol on the back.
The fuel is destined for the provincial town of Tataouine, where they will sell it at a mark-up on the side of the road or push it on to traders who distribute it further afield.
"We buy 100 bottles of 20 liters each -- they call them gallons -- each time. We have no other source of income. There is no work here," said Mohammed Abdel Haq, 57, pushing open the metal door to his home and welcoming visitors into a living room containing only two plastic chairs.
Even inside, the concrete walls are unpainted. Tattered rugs cover the floor and flimsy mattresses line the wall.
"We call our Libyan contacts in Nalout and say we want a 100 cans and agree on a place to meet on the border to pick it up."
Outside, five rusting pickup trucks without number plates sit empty, awaiting the next trip across the desert. Plastic containers soak the bare, sandy ground, ready for collection.
In the absence of proper border controls after uprisings that ousted autocratic leaders in Tunisia and Libya, smugglers plying unmarked desert routes are becoming ever bolder, and disputes are becoming ever more violent.
In April, a Libyan militia in the western town of Zawiya took at least 80 Tunisian migrant workers hostage to protest the arrest of three of its own members caught smuggling drugs by Tunisian border guards. Both the Tunisians and Libyans were freed after talks, Tunisia's news agency media said.
Earlier in April, five Tunisian smugglers were taken hostage by gunmen from Zuwara, another western Libyan town, in a dispute over fuel smuggling. They were later released.
And in February, Tunisian forces killed two gunmen and captured a third after clashes with a group of Islamist militants caught with arms smuggled from Libya.
GANGS IN THE NIGHT
The incidents highlight one of the many challenges Libya's National Transitional Council has faced in imposing its authority over myriad armed groups.
They also expose how underequipped and understaffed Tunisian border guards have been left helpless to crush a trade often carried out by heavily-armed gangs.
Those involved in the highly secretive arms trade are often part of well-connected gangs and travel in the dead of night with their lights turned off, locals say.
"We don't have the weapons to fight the smugglers. Sometimes we chase people but our cars are not good enough and the Libyans are armed. Sometimes they have rocket-propelled grenade launchers and other weapons and we need to think of our lives," said one Tunisian border guard at the Dehiba crossing, a flashpoint during the 2011 Libya war.
"The smuggling happens across the borders, not through the crossing, and it goes on daily, day and night."
On April 17, locals tried to cut off the road leading to the border crossing at Dehiba, which is surrounded on all sides by miles of endless scrub, to keep the Libyans out, the guard said.
"Because the border police arrested those Libyans over the drugs, their families started turning back Tunisians and refusing to sell them petrol," he said. "So the Tunisians were protesting against the Libyans."
SMUGGLING A LIFELINE
Smuggling is a lifeline in these Tunisian borderlands, where desert scrub stretches into Libya's barren western mountains.
Everything from livestock and food to beer and whisky makes the journey from Tunisia into Libya, where factories and farms have been hit by last year's rebellion and alcohol is banned. Even Tunisian-mined phosphate, official exports of which have been hit by strikes and protest, finds its way into Libya.
But by far the most popular trade is in petrol, subsidized and cheap in oil-exporting Libya, which is smuggled to Tunisia, a net fuel importer that has struggled with rising world prices.
Smuggling was rife before the Arab Spring toppled dictators, but it was a dangerous business carried out by a determined few.
In the security vacuum that has emerged since, locals say it has become the main livelihood in Tunisian border areas, remote, lacking factories or services and too dry for extensive farming.
Abdel Haq says his sons do up to 20 runs a day, bringing in up to 2,000 liters of petrol or diesel. Prices fluctuate depending on the supply but Abdel Haq sells onto traders who then sell on directly motorists in more heavily populated areas.
The further you go from the border, the higher the price, but Tunisian motorists who eventually have the fuel funneled into their tanks for upwards of 16 dinars ($10) are paying half what they would at a local petrol station.
Even the unmarked trucks that ply the trade were bought in Libya for 1,000 dinars each, much cheaper than in Tunisia.
"Before the revolution, sometimes the police would confiscate your car and take everything," Abdel Haq said. "Now they don't stop us because they know our situation. If there was something else for us we would stop turning to Libya."
The situation has deteriorated so far that Libya's chief of staff, Yousef al-Manquosh, paid a visit to Tunisia's defense ministry on April 24 to coordinate on border security.
"The shaky security situation on the border... requires a search for solutions and mechanisms to repel cross-border crime and the spread and smuggling of weapons," Tunisian Defence Minister Abdelkarim Zbidi said in a statement after the meeting.
The prime minister acknowledged the problem in a speech to parliament, saying the traffic with Libya had grown so large that it was affecting the Tunisian economy.
While analysts say that arms smuggling and the spread of militant groups poses more of a danger in countries such as Mali and Algeria, where insurgencies bubble, Tunisia could become a transit point for guns moving across North African borders.
LITTLE CHOICE BUT TO COMPLY
For locals, smuggling poses more of an economic challenge.
In the border areas near Dehiba, trucks carrying petrol and livestock are out on the road, under the eyes of police. All along the main roads, shacks sell petrol brought in from Libya.
But locals say the trade is becoming increasingly difficult as myriad checkpoints run by rival Libyan militias dot the road from Libya's western mountains to the Tunisian border. At each checkpoint, gunmen confiscate some gallons, hitting profits.
Tunisians who make the journey into Libya say they have little choice but to comply.
"The rebels are ruling there. I don't want to hear insults while I bring my petrol," said Mohammed Hawiwi, standing at the door of a shack meters from the Dehiba crossing.
"Some even fired at us. We haven't responded but they cannot do this if they want to keep bringing everything else into Libya from here."
Hawiwi says he is not a smuggler but does small-scale barter trade via the official border crossing, not through the desert. He says he has been forced to drive ever deeper into Libya's western mountains to collect his petrol, affecting his profit.
Tunisians are not allowed to fill up themselves at Libyan petrol stations, where a 20-litre tank goes for the equivalent of 3 dinars. Tunisians buy from Libyans at more than double that price in Libya and add their own markup on crossing the border.
Locals complain that food being smuggled or traded the other way -- into Libya -- has caused shortages and tripled the price of some fresh produce in Tunisian border areas. The price of tomatoes has risen more than five-fold in some border areas.
Many feel they are getting a raw deal. Locals say they feel a special bitterness as Tunisians across the frontier province of Tataouine opened their homes to Libyan refugees in the war.
"If you don't like it who do you talk to?" said Hawiwi. "There is no one to talk to. It is ruled by militias and they each have different ideas and change their minds."
(Editing by Sonya Hepinstall)