Algeria scours Sahara for missing foreigners after attack

Updated at 4:08 p.m. ET

ALGIERS, Algeria Algerian forces scoured the Sahara Desert on Tuesday, searching for five foreign energy workers who vanished during a chaotic four-day battle with hostage-taking Islamist militants.

One official says the men may have fled the sprawling complex during the fighting and gotten lost.

The four-day confrontation that began when al Qaeda-affiliated militants stormed the remote desert natural gas complex and took hostages early Wednesday, was punctuated by exploding cars, attacks from helicopters and a final assault by Algerian special forces.

In all, 37 hostages, including an Algerian security guard, and 29 militants were killed, but five other foreign workers remain unaccounted for.

"Are they dead? Did they attempt to flee the site after the attack like some other expatriates? Are they lost in the desert after taking a wrong turn?" an official who is part of Prime Minister Abdemalek Sellal's office told The Associated Press. "These are all questions we ask ourselves, but one thing is sure, everything is being done to know their fate."

The official spoke on condition of anonymity because he was not authorized to speak to the media.

Many foreign and Algerian workers hid and then slipped out of the sprawling facility into the hard featureless desert, eventually reaching the Algerian soldiers who had surrounded the complex.

The State Department has said three U.S. citizens were killed in the hostage standoff, while seven Americans made it out safely.

A law enforcement source told CBS News that the Americans are being debriefed by FBI agents in London and Germany, CBS News investigative senior producer Pat Milton reports. None of them are believed to have sustained serious injuries during the terrorist assault.

One of the hostages, Steve Wysocki of Elbert, Colo., told investigators he hid under his desk and then elsewhere to avoid detection for two days before he and others managed to escape, Milton reports.

As reported on "CBS This Morning" Tuesday, Briton Tony Grisedale took the same approach.

The Americans are expected to return to their hometowns by way of commercial airliners within the next 24 to 72 hours, Milton reports.

The Ain Amenas gas plant, jointly run by BP, Norway's Statoil and the Algerian state oil company, is located deep in the Sahara, some 800 miles south of the Mediterranean coast, with few population centers nearby.

More than 700 people work at the facility, including 130 foreigners from 26 countries who were targeted by the militants. The Islamists caught as many of those foreign workers as they could and wrapped some with explosives to use as human shields.

This part of the Algerian Sahara has none of the romance of the rolling velvet dunes of the Grand Erg Oriental to the north or the wild, twisted rock formations of Tassili N'Ajjer National Park farther south. Instead it is flat, dry and bitterly cold in the winter, with temperatures dropping to 37 degrees F at night.

The hostages could also have died in the fiery shootouts at the plant after being draped with explosive belts. Seven of the bodies recovered have yet to be identified because of their degraded condition, authorities said.

The $2 billion natural gas complex, which came online in 2006, was showing signs of life again Tuesday. Dozens of workers swarmed in to clean it up after experts went through and removed explosives that had been planted by militants.

The site was still littered, however, with the burnt-out carcasses of dozens of four-wheel drive vehicles destroyed in the clashes.

"I observed the damage and it isn't very serious," Algerian Energy Minister Youcef Yousfi said Tuesday in a visit to the site, according to the APS state news agency. "Once the damage has been evaluated, we will replace the equipment."

He said the plant, which provides 18 percent of the natural gas that is such a key Algerian export, would be brought back on line as soon as possible.

The audacious attack showed the improved capabilities of al Qaeda-linked groups in the Sahara. Some 32 militants — coming from across North Africa, with two from Canada — participated in the attack. Three were captured and the rest killed. Algeria said the group came from northern Mali, hundreds of miles away, sneaking across the borders of Libya and Niger before finally entering Algeria.

A group called the Masked Brigade claimed responsibility for the attack, saying it came in retaliation for Algeria's support of a recent French military operation against Islamist extremists in northern Mali and promised further such attacks. The group said the operation was two months in the planning.

Yousfi maintained that "Algeria had the means to secure our installations" and expressed doubt that any foreign companies would leave the oil-rich nation that is the third-largest supplier of natural gas to Europe.

Geoff Porter of North Africa Risk Consulting said the attack had sent shockwaves through the foreign oil and gas companies operating in Algeria and put them into a crisis mode.

"For the immediate term, this means that the Algerian hydrocarbons sector will enter a holding pattern for the next month or so, possibly resuming meaningful activity at the beginning of March," he said.

But he agreed with the minister that "it is extremely unlikely that Algeria will witness a mass exodus of foreign oil companies."

The Pentagon on Tuesday stopped short of saying al Qaeda's North Africa affiliate is definitely to blame for the attack, but it said there is good reason to believe the group had a leading role.

"When it comes to terrorist attacks of this sort in North Africa, AQIM has to be at the top of the list of suspects, I'll put it that way," said Pentagon press secretary George Little, referring to al Qaeda in the Islamic Maghreb.

The White House said the Obama administration is working with the Algerian government to learn more about what happened and did not echo concerns expressed by the British defense minister over the Algerian government's collaboration.

"We cannot lose sight of the fact that the blame for this lies with the terrorists," said White House press secretary Jay Carney.

Little told reporters there are strong indications that AQIM "had a hand" in the assault on an Algerian natural gas plant that left dozens of hostages and militants dead, but he would not be more specific.

"AQIM does what terrorist groups do — they plan and carry out attacks. I'll leave it at that," he said.

The State Department has not definitively declared that AQIM was responsible for the attack, but it has suggested the group played a leading role.

State Department spokeswoman Victoria Nuland said Tuesday the U.S. is consulting with Algerian government officials about who they believe was responsible for the attack.

"We don't have any reason to doubt AQIM's involvement in this attack," Nuland said, noting that the group has claimed responsibility.

Defense Secretary Leon Panetta has blamed the broader al Qaeda network.

Secretary of State Hillary Rodham Clinton last week described a "continuing effort by the terrorists, whether they call themselves one name or al Qaeda, to try to destroy the stability, the peace and security, of the people of this region.