Thirty-seven foreigners of eight nationalities were killed by Islamist militants in a well-planned attack on a remote gas plant, some of them executed with a bullet to the head, Algeria's premier said.
The grim body count was issued late Monday as the government gave its first death toll from the four-day crisis at the In Amenas gas plant, deep in the Sahara, which produced one of the worst hostage bloodbaths for years.
Prime Minister Abdelmalek Sellal said one Algerian was also killed and five other foreigners were still missing after the hostage-taking by militants who claimed to be retaliating against French military intervention in Mali.
"Thirty-seven foreigners of eight different nationalities" were killed during the siege, Sellal told reporters, adding that some of the hostages were gunned down in cold blood "with a bullet to the head".
With the death of the Algerian hostage, the overall toll among the captives stood at 38.
Sellal did not specify the foreigners' nationalities and seven of them remain unidentified. But governments have confirmed the deaths of seven Japanese, six Filipinos, three Americans, three Britons, two Romanians and one Frenchman.
A total of 29 militants were killed and three captured in the siege, which ended in a final showdown on Saturday between special forces and the remaining militants holed up in the sprawling gas complex.
Sellal said the militant gang included a Canadian, 11 Tunisians, three Algerians and others from northern Africa.
Some foreign leaders initially accused Algeria of keeping them in the dark about a military operation that many observers found hasty. But criticism then focused on the Islamist militants behind the crisis and broader threats.
Japan's Prime Minister Shinzo Abe condemned the act of "despicable terrorism". "Japanese people who work at the world's frontiers, innocent people, were victimised. It is extremely painful," he said.
Britain said it would use its chairmanship of the Group of Eight richest nations, which began this month, to focus on the terror threat following developments in Algeria and its conflict-torn neighbour Mali.
Prime Minister David Cameron said North Africa was becoming a "magnet" for jihadists from other countries, and that the threat there now outweighed that from Islamist hotbeds in Afghanistan and Pakistan.
Paris Match magazine published a warning from the Al-Qaeda splinter group that staged the Algeria raid, "Signatories in Blood", that France and other countries could now expect new attacks.
"The attack at In Amenas is only the beginning," a spokesman was quoted as saying, highlighting the offensive by French "crusaders" and "Zionist Jews" in Mali.
But Algeria's prime minister said the militants' invocation of France's 11-day-old offensive in Mali was a smokescreen, arguing that the attack on the gas plant had been planned for at least two months.
"Initially the security forces... tried negotiating in the hope of appeasing the hostage-takers. But these terrorists were determined. Their demands... were unreasonable and unacceptable," he added, justifying the army's intervention.
Most of the militants had entered the country from Mali, Sellal said, adding that the group's leader was Mohamed el-Amine Bencheneb, an Algerian militant known to the country's security services, who was killed in the siege.
The government has said special forces managed to free 685 Algerian and 107 foreign hostages, most of them on Thursday, during their first rescue operation.
The In Amenas plant, part of a natural-gas industry that is vital to Algeria's economy, is run by three companies including Britain's BP. Among others with employees caught up in the crisis was Japanese engineering firm JGC.
In a late-night news conference after Japan confirmed the deaths of seven of its nationals, all connected to the company, JGC spokesman Takeshi Endo fought back tears.
"We lost many capable employees. I cannot find the the right words. It's just unbearable," he said.
A French nurse said the fear of being raped and an overwhelming determination not to submit to "terrorists" had ensured she survived.
The nurse, identified only as Muriel, managed to flee the complex after spending the first day of the siege hidden with three other expatriates in offices that the gunmen failed to scour.
"These people were ready to commit any kind of barbaric act but I succeeded in thwarting them," she told Europe 1 radio.