The hostage standoff in southern Algeria came to a chaotic end Saturday when special forces stormed a remote gas plant. The four-day crisis left at least 23 hostages dead, along with all 32 militants.

Dozens of foreign workers are still missing, prompting fears that the death toll could rise even higher. It remains unclear if any hostages were rescued in the final assault.

Armed militants had first seized the plant, located in Ain Amenas, four days ago. Over the course of the standoff, Algerian troops surrounded the plant and exchanged gunfire with the militants.

Algeria’s handling of the crisis has prompted criticism from foreign countries worried about the fate of their citizens. However, many argue that the response was typical for a country that has historically refused to negotiate with terrorists, instead favouring military action.

"To avoid a bloody turn of events in response to the extreme danger of the situation, the army's special forces launched an intervention with efficiency and professionalism to neutralize the terrorist groups that were first trying to flee with the hostages and then blow up the gas facilities," Algeria's Interior Ministry said in a statement.

Shortly after Saturday’s operation, French President Francois Hollande was quoted in local media giving his support to the Algerian operation.

“There could be no negotiations with terrorists,” Hollande said.

Foreign Affairs Minister John Baird issued a statement Saturday, saying “Canada condemns the deplorable and cowardly attacks by terrorists” in Algeria.

"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,” Baird said.

"The thoughts and prayers of our entire country are with the families and friends of the innocent lives lost.”

Baird said his office does not believe Canadians or dual nationals were among the hostages. One permanent resident who had been on site is safe, and has since left Algeria.

In a statement issued from the White House, U.S. President Barack Obama also condemned the attack Saturday, and said the U.S. was prepared to provide whatever assistance the Algerian government needs in the aftermath of the attack.

"This attack is another reminder of the threat posed by al Qaeda and other violent extremist groups in North Africa. In the coming days, we will remain in close touch with the Government of Algeria to gain a fuller understanding of what took place so that we can work together to prevent tragedies like this in the future," the statement said.

Twice during the standoff the military attacked the two areas of the plant where hostages were being held.

On Saturday during the final assault, the state news agency said the military killed 11 militants, but not before seven hostages were killed. The latest death toll adds to a previous count that said 12 captives and 18 kidnappers had been killed, the government said.

The report, which quoted a security source, said the military launched its attack to prevent a fire, started by the extremists, from burning down the complex.

The report didn’t indicate if any hostages were alive after the attack. So far, an American from Texas, a French member of the facility’s security team and a Romanian have been identified as among the hostages who were killed. The British government is still trying determine what happened to six citizens, while Norway said five citizens are unaccounted for. The Malaysian government reported two missing citizens.

The entire refinery was mined with explosives and set to blow up, the Algerian state oil company Sonatrach said in a statement, adding that the process of clearing the explosives had begun. The Algerian media reported that the militants had planned to blow up the complex.

The sprawling plant in the country’s south is jointly run by BP, Norway’s Statoil and Algeria's state-owned oil company.

The statement from Algeria’s Interior Ministry said that over the course of the standoff, 685 Algerian and 107 foreign workers had been freed from the facility. After the standoff, soldiers found heavy machine-guns, rocket launchers, missiles and grenades, the military said.

The crisis has pushed the militancy afflicting the region into the spotlight, as al Qaeda-linked groups gain footholds through remote areas stretching from Mali to Libya.

On Wednesday, militants attacked the plant after creeping across the border from Libya.

They attempted to capture two buses that were transporting foreign workers to the airport. The buses’ military escort managed to drive off the attackers, but not before a U.K. citizen and an Algerian – believed to be a security guard – were killed.

The defeated militants then set their sights on the gas plant and seized hostages, Algerian government officials said.

Food services worker Chabane told AP that when he heard the militants speaking with Libyan, Egyptian and Tunisian accents he fled out a window and went into hiding. He said he overheard them say they had caught a British citizen.

"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.' A few minutes later, they blew him away," Chabane said.

One American, a Briton and a French citizen were among the dead, along with a number of Algerians. Escaped Algerian workers described seeing people of many nationalities, including Japanese, shot down.

Meanwhile, a Canadian who was among the employees at the facility when the attack was launched on Wednesday is safe.

The group claiming responsibility said the attack was in response to Algeria’s support for France’s military operation in Mali.

France has led a military intervention in the small African nation, as it battles al Qaeda-linked rebels in the north.

On Saturday, Hollande said of the hostage-taking: “If there was any need to justify our action against terrorism, we would have here, again, an additional argument.”

Terrorism expert John Thompson told CTV News Channel on Saturday extremists are attempting to hang on to their control of the region.

“Now that the French are involved in helping Mali, it’s enough that they launched this raid into Algeria to try and complicate the situation,” said Thompson who works with the Mackenzie Institute think tank.

On Friday, Ottawa said it was aware of reports that a Canadian may have been among the hostage-takers.

Reports surfaced after Mauritanian news agency Agence Nouakchott d'Information quoted an unnamed source affiliated with the militants, who said the group of hostage-takers includes people from Mali, Egypt, Niger, Mauritania and Canada.

The Department of Foreign Affairs said it was “pursuing all appropriate channels to seek further information” and it is in communication with Algerian authorities.