The Algerian government said it was forced to intervene due to the militants' stubbornness and their desire to escape with the hostages.
"An important number of hostages were freed and an important number of terrorists were eliminated, and we regret the few dead and wounded," Algerian Communications Minister Mohand Said Oubelaid told national media, adding that the "terrorists are multinational," coming from several different countries with the goal of "destabilizing Algeria, embroiling it in the Mali conflict and damaging its natural gas infrastructure."
Islamists from the Masked Brigade, a Mali-based Al Qaeda offshoot, who have been speaking through a Mauritanian news outlet, said Algerian helicopters opened fire as the militants tried to leave the vast energy complex with their hostages. They claimed that 35 hostages and 15 militants died in the attack and only seven hostages survived.
Algeria's official news service, meanwhile, earlier claimed that 600 local workers were freed in the raid and half of the foreigners being held were rescued. Many of those locals were reportedly released on Wednesday, however, by the militants themselves.
One Irish hostage was confirmed safe: supervising electrician Stephen McFaul, whose mother said he would not be returning to Algeria.
"He phoned me at 9 o'clock to say Al Qaeda were holding him, kidnapped, and to contact the Irish government, for they wanted publicity. Nightmare, so it was. Never want to do it again. He'll not be back! He'll take a job here in Belfast like the rest of us," said his mother, Marie.
Dylan, McFaul's 13-year-old son, started crying as he talked to Ulster Television. "I feel over the moon, just really excited. I just can't wait for him to get home," he said.
In Washington, White House Press Secretary Jay Carney said the Obama administration was "concerned about reports of loss of life and are seeking clarity from the government of Algeria."