Fear and confusion: how workers ran for their lives as brutal onslaught began

It was more than 24 hours after jihadists had stormed the Saharan gas plant, taking scores of hostages, that foreign workers were loaded onto a convoy of trucks.

The militants appear to have anticipated that the Algerian military would storm the facility rather than negotiate. By mid-morning on Thursday some of the hostages had their mouths taped and explosives hung around their necks. It is unclear whether the fighters were trying to flee the refinery near Algeria's desert border with Libya. In any case they did not get far.

Bombs rained down on four of the five vehicles and the opening phase of Algeria's fateful rescue operation at the In Amenas gas field had begun. Among the hostages was Irishman Stephen McFaul, who later recounted to his family what had happened. "They were moving five jeep-loads of hostages from one part of the compound," Brian McFaul, the hostage's brother, told Reuters. "At that stage they were intercepted by the Algerian army. The army bombed four out of five of the trucks, and four of them were destroyed."

Mr McFaul, who successfully escaped the siege after the bombs missed the vehicle he was in, believes that hostages in the other vehicles did not survive. As of last night, there were still more than 30 foreign hostages unaccounted for.

Algerian forces had ringed the complex soon after militants announced their presence by attacking two buses carrying gas workers to a nearby airport at 5.30am local time on Wednesday.

Foreign governments, aware that at least 10 nationalities were among the hostages, had been urging caution. The exact timing of the assault is unclear as several witness accounts suggest the Algerian army was firing on the complex soon after the siege began. A Japanese hostage, whose fate is unknown, told Al Jazeera by telephone that army snipers had wounded him and a Norwegian hostage prior to the helicopter attack.

PM David Cameron first heard that the storming of the plant was under way as he spoke with his Algerian counterpart at 11am on Thursday. Around the same time, jihadists from the "Signed in Blood" militant group, talking to a radio station in Mauritania, said that Algerian helicopters were strafing the complex.

Official estimates suggest there were as many as 600 Algerian employees and 132 foreign workers at the Tigantourine complex. Reports suggest the militants had sorted the Algerian workers from the foreigners, even telling them that they would not target Muslims, "only Christians and infidels".

Most of the ex-pats were in the residential area, two miles from the gas pumping station, built there in case of an accidental explosion.

Since the attack, many of them had employed different tactics to hide and survive. In the cafeteria, where 40 workers had waited since the first shots were heard, gunmen were sorting Algerians from other nationalities. One European man was shot in front of the others without warning. After the shooting, five darker-skinned foreigners pretended to be Algerian. They were able to escape when the locals were allowed to leave on a bus.

Frenchman Alexandre Berceaux, who worked with the site's catering company, took a different tack. He fled the chambers where other workers were being held and locked himself in another room, hiding under a bed.

From his hiding place, on Thursday morning he heard "intervals of heavy fire" and helicopters outside and assumed that a battle for the plant had begun. He had been under the bed for 40 hours by the time he heard Algerian colleagues' voices saying it was safe to open the door. He assumed the soldiers he saw on the other side, in green uniforms, were Algerian army.

Azedine, 27, the plant radio operator, said he is still in shock. He saw the body of his French supervisor. "My supervisor was a great man; I learned a lot from him. He had been shot, but I did not see the execution. All I saw was his body when I ran with some colleagues to leave the base. We are very lucky, but the face of my French supervisor is still before my eyes."

Others were not so fortunate. One Briton, Garry Barlow, was forced to sit at his desk with plastic explosives strapped to his chest. A friend whom he telephoned in the UK was told by him: "I'm sat here at my desk with Semtex strapped to my chest. The local army have already tried and failed to storm the plant, and they've said that if that happens again they are going to kill us all." His fate is not yet known.

Many of the straggle of survivors simply ran for it. Khaled, an Algerian engineer for Sonatrach, told L'Express that he had been held with several others in a games room. "There was a stampede," he said, and some people forced open the security door. "Then we all started to run."

Algeria's hardman: General Tartag

The bloody Algerian army assault on the BP gas complex on Thursday was led by an uncompromising terrorist hunter known as "the bombardier".

General Arthman "Bachir" Tartag, 60, the deputy head of the security services, has orders to eliminate the remaining Al-Qa'ida activity in Algeria. North African experts in Paris say he would have taken the attack on the gas complex as a personal affront.

"He has a reputation for brutality which goes back to the Algerian civil war in the 1990s," one expert said.

Lazare Beullac, the editor of the French newsletter Maghreb Confidentiel, said General Tartag's instinct would be to destroy Islamist militants rather than to rescue hostages.

"In any case the Algerians never negotiate in these situations," Mr Beullac said. "They regard hostages as people condemned to death."

General Tartag is the head of the Algerian Internal Security Department and the deputy head of the country's overall security apparatus.

His appointment to head the siege operations – conducted mostly by special forces known as "the Ninjas" – suggests that Algiers had contemplated a bloody outcome from the beginning.

John Lichfield