The Algerian government says 32 militants and 23 captives were killed during the three-day military operation to end the hostage crisis at a natural gas plant in the Sahara.

The provisional death toll was issued by the Interior Ministry on Saturday after the special forces operation crushed the last holdout of the militants at the gas refinery, resulting in 11 extremists killed along with seven hostages.

A total of 685 Algerian and 107 foreigner workers were freed over the course of the standoff, which began on Wednesday, the statement added.

The military also confiscated machine-guns, rocket launchers, missiles and grenades attached to suicide belts.

The ministry added that the militants involved consisted of 32 men of various nationalities, including three Algerians. A news agency in Mauritania — Agence Nouakchott d'Information — has quoted an unnamed source with the militant group who says the hostage-takers included people from Mali, Egypt, Niger, Mauritania and Canada.

Canadian Foreign Affairs Minister John Baird said that Canada condemns the kidnappings, and called the attacks "deplorable and cowardly."

The minister said it's believed no Canadians or dual nationals were among the hostages and a permanent resident of Canada who was at the site is safe and has left Algeria.

He made no mention of the alleged Canadian hostage-taker reported by ANI.

The minister said while the full scale and exact details of the situation remain unclear, Canadian officials remain in close contact with Algerian authorities to seek further information.

Britain's Secretary of State for Defence Philip Hammond, left, speak to the media with U.S. Defense Secretary Leon Panetta in London on Saturday. (Jacquelyn Martin/Associated Press)

In a bloody finale, Algerian special forces stormed the natural gas complex in the Sahara desert on Saturday to end the standoff with Islamist extremists that left at least 19 hostages and 29 militants dead. Dozens of foreign workers remain unaccounted for, leading to fears the death toll could rise.

The siege transfixed the world after radical Islamists linked to al-Qaeda stormed the complex, which contained hundreds of plant workers from all over the world, and then held them hostage surrounded by the Algerian military and its attack helicopters for four tense days that were punctuated with gunbattles and dramatic tales of escape..

Ottawa said Friday it is "pursuing all appropriate channels to seek further information" and is in close contact with Algerian authorities.

No negotiation

Algeria's response to the crisis was typical of the country's history in confronting terrorists, favouring military action over negotiation, which caused an international outcry from countries worried about their citizens. Algerian military forces twice assaulted the two areas where the hostages were being held with minimal apparent mediation — first on Thursday and then on Saturday.

Sonatrach, the Algerian state oil company running the site along with BP and Norway's Statoil, said the entire refinery had been mined with explosives, and the process of clearing it out had begun, indicating the militants planned to blow up the complex — one of the largest in oil and gas-rich Algeria.

Al-Qaeda strong in the wastes of the Sahara

Algeria has fought its own Islamist rebellion since the 1990s, elements of which later declared allegiance to al-Qaeda and then set up new groups in the poorly patrolled wastes of the Sahara along the borders of Niger, Mali, Algeria and Libya, where they flourished.

The standoff has put the spotlight on al-Qaeda-linked groups that roam these remote areas, threatening vital infrastructure and energy interests. The militants initially said their operation was intended to stop a French attack on Islamist militants in neighbouring Mali — though they later said it was two months in the planning, long before the French intervention.

Unidentified rescued hostages in Ain Amenas, Algeria, in an image taken from television Friday Jan. 18. (Canal Algerie/Associated Press)

The Algerian government said the militants crept across the border from Libya, 100 kilometres away, while the militants later said they came from Niger, hundreds of miles to the south.

On Thursday, Algerian helicopters kicked off the military's first assault on the complex by opening fire on a convoy carrying both kidnappers and their hostages, resulting in many deaths, according to witnesses.

The hostages who escaped recounted their ordeal and said they faced danger from both the kidnappers and the military.

Casualty figures varied widely. While the Algerian government has only admitted to 19 hostages dead so far, the militants claimed through the Mauritanian news website ANI that the helicopter attack alone killed 35 hostages.

One American, from Texas, is among the dead and least one Briton, a Frenchman and Algerians have also died in the standoff. Escaped Algerian workers describe seeing people of many nationalities, including Japanese, shot down.

French Defence Minister Jean-Yves Le Drian said Saturday that the 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.

Statoil CEO Helge Lund said Saturday that there were five Norwegians unaccounted for, while BP said four of its 18 employees were still unaccounted for.

Romanian Prime Minister Victor Ponta said Saturday one Romanian hostage was killed in the course of the siege, while four escaped unharmed. The Malaysian government said two of its citizens were still missing.

The attack by the Mali-based 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.

An Algerian military helicopter flies over Amenas city, south east of Algiers, on Saturday near where Islamist militants had been holding foreigners hostage. (Louafi Larbi/Reuters)

He said militants targeted Algeria because they expected the country to support the international effort to root out extremists in neighbouring 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 names 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.

A man identified only as Chabane, 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."

With files from CBC News