ALGIERS: Thirty-seven foreigners of eight different nationalities were killed during the hostage crisis at an Algerian gas plant that was overrun by Islamist gunmen, Prime Minister Abdelmalek Sellal said on Monday.

"Thirty-seven foreigners of eight different nationalities," died during the four-day siege, Sellal told

a news conference in Algiers, without specifying their nationalities.

One Algerian also lost his life, bringing the overall toll to 38, while five foreigners were still missing, he said, adding that seven of the dead had still not been identified.

Among those that other official sources have already confirmed to have died in the siege were seven Japanese, six Filipinos, three Americans, three Britons, two Romanians and one Frenchman.

During the army's final assault on the plant, Sellal said the remaining gunmen executed several hostages by shooting them in the head.

The interior ministry had on Saturday given a preliminary toll of 23 foreign and Algerian hostages killed during the hostage crisis, which ended on Saturday with Algerian forces storming the remaining part of the complex still in militant hands.

Some foreign leaders initially accused Algeria of keeping them in the dark about an operation that many observers found hasty, but criticism then focused on the Islamist militants behind the attack.

Sellal on Monday defended the army's muscular response to the kidnapping, calling the demands of the gunmen "unacceptable."

"Initially the security forces... tried negotiating in the hope of appeasing the hostage-takers. But these terrorists were determined. Their demands... (on the release of Islamist prisoners) were

unreasonable and unacceptable," he said.

A total of 29 militants were killed and three captured during the siege, while the special forces managed free 685 Algerian and 107 foreign hostages.

Eleven of the hostage-takers, who were also demanding an end to French military intervention in Mali, were Tunisian and another three Algerian, with the rest Canadian, Egyptian, Malian, Nigerien and Mauritanian.

Sellal said the 32 militants came from northern Mali, and that the group's leader was Mohamed el-Amine Bencheneb, an Algerian militant known to the country's security services, who was killed during the army's assault.