(CNN) -- Algerian troops ended a hostage crisis at a remote gas facility Saturday with one last, bloody assault, Algerian and Western officials said, after three days of chaos and confusion left dozens dead and fanned fears of a new terror front in Africa.

At least 23 hostages and 32 "terrorists" were killed around the sprawling facility in eastern Algeria's desert, Algerian state news said Saturday, citing the military. Some 685 Algerian workers and 107 foreigners have been freed, those reports said.

It is not clear just how many people are still unaccounted for. A senior U.S. official said two Americans were among that number.

The saga closed after a "final" assault, which itself contributed to the deaths of seven hostages and 11 militants, according to Algerian state media reports.

An Algerian Radio report did not specify the nationalities of those killed. CNN is unable to verify the state media figures on the deaths.

Afterward, Algeria's military continued to clear mines planted by militants, the official Algerian Press Service reported, citing the country's state-owned oil and gas company.

"While the site is still dangerous and there may be explosives that will need to be dealt with, the terrorist incident is now over," said British Prime Minister David Cameron, citing his conversation with his Algerian counterpart.

The militant siege caught the world's attention as it ensnared citizens from several nations and dragged on for days.

Algerian authorities said they believe the attack was revenge for allowing France to use Algerian airspace for an offensive against Islamist militants in neighboring Mali.

Whatever the rationale, the scale and gore of the terror has stirred world leaders to press for action beyond Algeria, especially with Islamic extremists asserting themselves more and more in recent weeks.

"Let me be clear: There is no justification for taking innocent life in this way," Cameron said. "Our determination is stronger than ever to work with allies ... around the world to root out and defeat this terrorist scourge and those who encourage it."

British Foreign Secretary William Hague said Algerian authorities "certainly worked very hard to try to save the lives of people from other countries. I think it's actually too early to pass judgment on (the Algerian military operation)."

U.S. President Barack Obama said his administration would work with other countries to "combat the scourge of terrorism in the region, which has claimed too many innocent lives. This attack is another reminder of the threat posed by al Qaeda and other violent extremist groups in North Africa."

In a statement, Obama said the United States will work with Algeria to prevent future such incidents.







Bloody Algeria Hostage Crisis Ends After Final Assault