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By Alastair Macdonald and Lamine Chikhi
LONDON/ALGIERS, Jan 18 (Reuters) - The In Amenas gas plantfelt impregnable to many who worked there - walled in, hundredsof miles from anywhere and with the Algerian army constantlypatrolling its desert approaches.
That was a mirage. Libya, an ex-police state turned armsbazaar and now open for jihad, lies just 50 empty miles away.And in any case, the enemy was probably already inside thegates.
At least some of up to 70 Islamist guerrillas who stormed inbefore dawn on Wednesday launched their operation hours earlier,barrelling over smugglers tracks across the Libyan border justafter midnight, an Algerian security official told Reuters,citing evidence from mobile phones traced to the militants.
The ease with which they entered the fortified housingcompound and nearby natural gas plant also left Algerians inlittle doubt the gunmen had allies among people at the site.
"They had local cooperation, I'm sure, maybe from drivers orsecurity guards, who helped the terrorists get into the base,"said Anis Rahmani, editor of Algeria's Ennahar newspaper and awriter on security issues who said he was briefed by officials.
Officials in this secretive country said they had discoveredcases before when Islamist rebels succeeded in having fellowmilitants employed by international energy companies. One toldReuters it was possible insiders had cooperated at In Amenas.
Locally hired workers who escaped told Reuters of seeing thegunmen moving around the sprawling facility with confidence,apparently familiar with its layout and well prepared.
The militants said they launched the raid to halt Frenchmilitary intervention in neighbouring Mali, which began a weekago, however the link is not yet clear. Several European andU.S. officials said the assault seems too elaborate to have beenplanned in such a short time.
It is possible the attack would have happened anyway, orthat the French military operation provided a trigger to carryout an attack based on preparations done earlier.
Much may never become clear. The raid was carried out in aregion closed to outsiders within a country whose government isunused to sharing sensitive information with the public.
First word of trouble came crackling over a walkie-talkie tothe communications room at In Amenas, where a 27-year-old radiooperator called Azedine logged a contact with a bus driver who,at 5:45 a.m. (0445 GMT), left to take some foreigners to theairstrip at the town of In Amenas, some 50 km (30 miles) away.
"Moments after the bus left, I heard shooting, a lot ofshooting, and then nothing," Azedine told Reuters on Friday.
Two people, one British, one Algerian were killed on twobuses heading for the airport. It is not clear whether thatincident was part of the plan that secured the militants accessto the compound. Almost immediately after the bus skirmish, theywere inside, in at least three vehicles.
People who have worked at the site, which sits with its backto cliffs in the dunes, say there was normally an overnightcurfew on movement in the area, leaving it unclear how thegunmen were able to get so close before being challenged. Theirinitial approach may have been well off the main roads.
Freed hostages spoke of an alarm being raised, of frightenedpeople staying in their offices or accommodation.
Azedine saw a gunman put on the ID badge of a Frenchsupervisor who had been shot dead.
Rapidly the area was surrounded by heavily armed Algeriantroops, with tanks, armoured vehicles and helicopter gunshipsfrom a nearby military base. The government in Algiers vowednever to negotiate.
SMUGGLERS' TRAILS
People familiar with the site, operated by Britain's BP andStatoil of Norway along with Algeria's state energy company,said a barracks housing several hundred soldiers lies along thethree km (two miles) of road separating the many buildings ofthe accommodation compound from the industrial plant.
A former senior Algerian government official said guardsappeared to have been caught napping: "They have all kinds ofequipment, detailed surveillance, cameras," he said. "They werecaught maybe at the right time, at five in the morning."
But he also acknowledged the militants may have had helpamong the local workforce: "Out of 700 Algerians, I am sure theywill find a couple who will cooperate. It always happens."
Militant leaders like Taher Ben Cheneb, said by officials tohave led the operation and to have been killed on Thursday, havestoked resentment among southerners at the way foreigners andnortherners dominate the better paid jobs in the oil fields.
Ben Cheneb, described as a high school maths teacher in his50s, led the Movement of the Islamic Youth in the South.Security expert Rahmani said he joined forces for this operationwith followers of Mokhtar Belmokhtar, a veteran of Afghan warsand a leading figure in Al Qaeda in the Islamic Maghreb (AQIM)who recently formed a new group named Mulathameen.
The two men had cooperated before, Rahmani said, notably indamaging an airliner in 2007 at Djanet, further to the south.
While Ben Cheneb's group appeared to have moved on In Amenasfrom a base inside Algeria, Rahmani said, Belmokhtar's men, ledby Abu El Bara, appeared to have come in from Libya.
Noting the one-eyed Belmokhtar's reputation as a cigarettesmuggler as well as a holy warrior - locals call him the "MisterMarlboro" - he added: "They use the same backroads as thesmugglers. You need a perfect knowledge of the Sahara to do it.
"They can use the same wells as the smugglers, the same fueldumps hidden in the desert."
More than a decade after Algeria's civil war killed some200,000 people, Islamist fighters roam the sandy wastes ofAfrica's biggest country, mixing smuggling and kidnapping forransom with opposition to the political establishment that hasruled in Algiers since French colonists left half a century ago.
These groups have been energised by the return of heavilyarmed ethnic Tuaregs and others from Libya, where they fought asmercenaries for Muammar Gaddafi until his overthrow in 2011. Thenew Libyan authorities are struggling to control their own deepsouth and it provides a launchpad for raids across the frontier.
Images from Libya's civil war, of men in desert robespowering across the dunes in pick-up trucks mounted with heavyweapons ranging from machineguns to missile-launchers, have beentransferred, along with arms and men, to conflict in the Sahara.
Mali's army melted away last year, ceding control ofnorthern towns like Timbuktu as fighters came back from Libya.
ARMY ASSAULT
While security forces seek to control their frontiers, thetracts of sand are vast, borders among the half dozen countriesaround the desert are unmarked, and the big money that can bemade from illicit trade or kidnapping tourists and Westernengineers can be used to buy favours from ill-paid officials.
Al Qaeda says it is fighting for a Muslim caliphate thattranscends artificial borders in the Maghreb set by colonialpowers.
Once inside the facility, militants, including bearded,ragged fighters and others in more urban dress, herded groups ofWesterners together. Hundreds of Algerians were guarded moreloosely. One Algerian worker told Reuters the gunmen said theywere only interested in killing "Christians and infidels".
Several former hostages described the attackers, from theiraccents, as appearing to be Libyan or Egyptian as well asAlgerian. Officials said many of 18 dead gunmen were foreign.
Algeria told Western governments, which voiced dismay at thestorming of the facility on Thursday, that troops moved in onlybecause guerrillas were trying to leave with hostages, possiblyhoping to reach the Malian border.
The captors loaded hostages into a convoy. Special forcesbacked by helicopters moved in around noon, some 30 hours afterthe plant was seized.
In what appears to have been the deadliest part of thesiege, as described by the family of Irish survivor StephenMcFaul, government forces bombed the convoy, blasting apart fourvehicles full of hostages. McFaul was in a fifth truck whichcrashed. He dashed for his life and escaped, and believes allthose in the other vehicles were killed.
During Thursday, most of the hundreds of people at the sitewere able to flee.
By Friday night, it remained unclear how many of the gunmenand their hostages were still in the facility - though bothgroups might number in the dozens. Norway's prime minister saidthe operation at the larger, residential compound seemed to beover and troops were now surrounding the industrial site.
But this left Western governments and intelligenceofficials, long used to difficult relations with Algeria whichis proud of its sovereignty, desperate for hard facts about thefate of their nationals.
