Ruben Andrada, 49, a Filipino civil engineer who works as one of the project management staff for the Japanese company JGC Corp., described how he and his colleagues were used as human shields by the kidnappers, which did little to deter the Algerian military.
On Thursday, about 35 hostages guarded by 15 militants were loaded into seven SUVs in a convoy to move them from the housing complex to the refinery, Andrada said. The militants placed "an explosive cord" around their necks and were told it would detonate if they tried to run away, he said.
"When we left the compound, there was shooting all around," Andrada said, as Algerian helicopters attacked with guns and missiles. "I closed my eyes. We were going around in the desert. To me, I left it all to fate."
Andrada's vehicle overturned allowing him and a few others to escape. He sustained cuts and bruises and was grazed by a bullet on his right elbow. He later saw the blasted remains of other vehicles, and the severed leg of one of the gunmen.
The site of the gas plant spreads out over several hectares (acres) and includes a housing complex and the processing site, about a mile (1.6 kilometers) apart, making it especially complicated for the Algerians to secure the site and likely contributed to the lengthy standoff.
"It's a big and complex site. It's a huge place with a lot of people there and a lot of hiding places for hostages and terrorists," said Col. Richard Kemp, a retired commander of British forces who had dealt with hostage rescues in Iraq and Afghanistan. "These are experienced terrorists holding the hostages."
While the Algerian government has only admitted to 23 hostages dead so far, the militants claimed through the Mauritanian news website ANI that the helicopter attack alone killed 35 hostages.
One American, a Texan — Frederick Buttaccio from the Houston suburb of Katy — was among the dead. "Fred spent a lifetime experiencing the world and always respecting everyone he met, no matter their position, culture, or religion," the family said in a statement Saturday.
President Barack Obama said in a statement Saturday that the U.S. stood ready to provide whatever assistance was needed in the wake of the attack.
"This attack is another reminder of the threat posed by al-Qaida and other violent extremist groups in North Africa. In the coming days, we will remain in close touch with the Government of Algeria to gain a fuller understanding of what took place so that we can work together to prevent tragedies like this in the future," the statement said.
French Defense Minister Jean-Yves Le Drian said Saturday that a Frenchman killed, Yann Desjeux, was a former member of the French special forces and part of the security team. The remaining three French nationals who were at the plant are now free, the Foreign Ministry said.
The British government said Saturday it is trying to determine the fate of six people from Britain who are either dead or unaccounted for.
Prime Minister David Cameron of Britain said, "There is no justification for taking innocent life in this way. Our determination is stronger than ever to work with allies right around the world to root out and defeat this terrorist scourge and those who encourage it."
The Norwegian government said there were five Norwegians unaccounted for.
Romanian Prime Minister Victor Ponta said Saturday one Romanian hostage was killed in the course of the siege, while the Malaysian government said two of its citizens were still missing.
The attack by the Masked Brigade, founded by Algerian militant Moktar Belmoktar, had been in the works for two months, a member of the brigade told the ANI news outlet. He said militants targeted Algeria because they expected the country to support the international effort to root out extremists in neighboring Mali and it was carried out by a special commando unit, "Those Who Signed in Blood," tasked with attacking nations supporting intervention in Mali.
The kidnappers focused on the foreign workers, largely leaving alone the hundreds of Algerian workers who were briefly held hostage before being released or escaping.
Several of them arrived haggard-looking on a late-night flight into Algiers on Friday and described how the militants stormed the living quarters and immediately separated out the foreigners.
Mohamed, a 37-year-old nurse who like the others wouldn't allow his last name to be used for fear of trouble for himself or his family, said at least five people were shot to death, their bodies still in front of the infirmary when he left Thursday night.
Chabane, an Algerian who worked in food services, said he bolted out the window and was hiding when he heard the militants speaking among themselves with Libyan, Egyptian and Tunisian accents. At one point, he said, they caught a Briton.
"They threatened him until he called out in English to his friends, telling them, 'Come out, come out. They're not going to kill you. They're looking for the Americans,'" Chabane said.
"A few minutes later, they blew him away."
Paul Schemm reported from Rabat, Morocco. Associated Press writers Aomar Ouali in Algiers; Oliver Teves in Manila, Philippines; Elaine Ganley in Paris; Sylvia Hui in London; Jan M. Olsen in Copenhagen; and Peter Spielmann at the U.N. contributed to this report.