Algerian special forces launched a “final assault” on the facility at the In Amenas site on Saturday. Al Qaeda-linked militants calling themselvesthe "Signatories in Blood" group raided the plant on Wednesday, demanding an end to French military intervention in Mali.
Algeria's Commuications Minister, Mohamed Said, told a radio station he fear the death toll could rise as more information about the four-day crisis emerges.
In some of the latest developments:
- The Algerian Interior Ministry says special forces killed all 32 Al Qaeda-linked hostage takers.
- Algerian witnesses say the militants killed nine Japanese captives during the final standoff with the Algerian military. A Japanese engineering firm says 10 Japanese and seven foreign workers from its firm are unaccounted for.
- British Prime Minister David Cameron says three Britons are confirmed dead. Three more are unaccounted for.
- Five workers for Norway's Statoil are unaccounted for.
A Frenchman, Yann Desjeux, was among the dead. A former member of the military, he was reportedly worked for a logistics firm and owned a restaurant in the town of Anglet.
On Sunday, the French Foreign Minister, Laurent Fabius, told private radio station Europe 1 the events showed the need to be "relentless in the face of terrorism".
"These are killers, they rob, they rape, they ransack," Fabius said, adding he felt "shocked" that "it is the Algerians who are being called into question."
The comments echoed French President Françios Hollande's response on Saturday.
"When there is a hostage-taking with so many people involved and such coldly determined terrorists, ready to kill their hostages -- which they did -- a country such as Algeria has had ... the most appropriate responses because there could be no negotiations," Hollande told reporters in Tulle, south-central France.
The Algerian government had come under heavy criticism, especially from the United Kingdon and Norway, over the lack of information and warning about the initial response to the crisis on Thursday.
British Prime Minister David Cameron stressed that responsibility "lies squarely with the terrorists who launched this vicious and cowardly attack", and said he would put the issue of global terrorism at the top of the agenda of this year's G8 summit.
He also refused to criticise Algeria, saying the attack had been an "extremely difficult" situation to deal with.
With the crisis over, experts began to clear the complex of bombs planted by the Islamists, said Sonatrach, the Algerian firm that runs the gas plant jointly with Britain's BP and Norway's Statoil.