Updated at 7:45 p.m. ET
N'DJAMENA, Chad Chad's military chief announced late Saturday that his troops deployed in northern Mali had killed Moktar Belmoktar, the terrorist who orchestrated the attack on a natural gas plant in Algeria that left 37 foreigners dead.
The French military, which is leading the offensive against al Qaeda-linked rebels in Mali, said they could not immediately confirm the information.
Known as the "one-eyed," Belmoktar's profile soared after the mid-January attack and mass hostage-taking on a huge Algerian gas plant.
Mark Cobb, one of the five Americans who survived the attack, spoke to "60 Minutes" contributor Charlie Rose in an interview broadcast on CBS last month.
"I knew as the highest-ranking American on the site, I would be a prize," Cobb told Rose. "They put the highest value on American hostages, British hostages and French hostages. I heard them kick open the front door. That's I guess at the point where in all honesty I would say I felt pure terror."
Cobb escaped through a hole in the perimeter fence.
Canadian diplomat Robert Fowler was his hostage in 2008.
"He's very tough," Fowler told CBS News. "He seems physically demanding. He demands a lot of his people and therefore, yes, I'd say he's a tough enemy."
Multinational forces have been looking for Belmoktar. CBS News correspondent Kelly Cobiella reports the United States is flying drones in the area.
Local officials in Kidal, the northern town that is being used as the base for the military operation, cast doubt on the assertion, telling The Associated Press that Chadian officials are attempting to score a PR victory to make up for the significant losses they have suffered in recent days.
Belmoktar's purported death comes a day after Chad's president said his troops had killed Abou Zeid, the other main al Qaeda commander operating in northern Mali.
If both deaths are confirmed, it would mean that the international intervention in Mali had succeeded in decapitating two of the pillars of al Qaeda in the Sahara.
"Chad's armed forces in Mali have completely destroyed a base used by jihadists and narcotraffickers in the Adrar and Ifoghas mountains" of northern Mali, Army Chief of Staff Gen. Zakaria Ngobongue said in a televised statement on state-owned National Chadian Television. "The provisional toll is as follows: Several terrorists killed, including Moktar Belmoktar."
The French military moved into Mali on Jan. 11 to push back militants linked to Belmoktar and Abou Zeid and other extremist groups who had imposed harsh Islamic rule in the north of the vast country and who were seen as an international terrorist threat.
France is trying to rally other African troops to help in the military campaign, since Mali's military is weak and poor. Chadian troops have offered the most robust reinforcement.
In Paris, French military spokesman Col. Thierry Burkhard said that he had "no information" on the possibility that Belmoktar was dead. The Foreign Ministry refused to confirm or deny the report.
A spokesman for Chad's presidential palace did not immediately return a request for comment.
In Kidal in northern Mali, an elected official, who requested anonymity because he was not authorized to speak to the press, told the AP that he did not believe that Belmoktar was dead and waved off the claim as an attempt by Chad to explain the loss of dozens of their troops to a grieving nation.
"These last few weeks, the Chadians have lost a significant number of soldiers in combat. (Claiming that they killed Belmoktar) is a way to give some importance to their intervention in Mali," said the official, who keeps in close contact with both French and Malian commanders in the field.
Belmoktar, an Algerian, is believed to be in his 40s, and like his sometimes partner and sometimes rival, Abou Zeid, he began on the path to terrorism after Algeria's secular government voided the 1991 election won by an Islamic party.
Both men joined the Armed Islamic Group, or GIA, and later its offshoot, the GSPC, a group that carried out suicide bombings on Algerian government targets.
Around 2003, both men crossed into Mali, where they began a lucrative kidnapping business, snatching European tourists, aid workers, government employees and even diplomats and holding them for multimillion-dollar ransoms.
The Algerian terror cell amassed a significant war chest, and joined the al Qaeda fold in 2006, renaming itself al Qaeda in the Islamic Maghreb.
Belmoktar claims he trained in Afghanistan in the 1990s, including in one of Osama Bin Laden's camps. It was there that he reportedly lost an eye, earning him the nickname "Laaouar," Arabic for "one-eyed."
Until last December, Belmoktar and Abou Zeid headed separate brigades under the flag of al Qaeda's chapter in the Sahara. But after months of reports of infighting between the two, Belmoktar peeled off, announcing the creation of his own terror unit, still loyal to the al Qaeda ideology but separate from al Qaeda in the Islamic Maghreb.
It was this group that launched the fatal attack on a BP-operated natural gas plant in southeastern Algeria in retaliation for the French-led military intervention in Mali.
In the attack and in the subsequent rescue attempt, 37 people were killed inside the complex. Belmoktar claimed responsibility for the attack within hours, immediately catapulting him into the ranks of international terrorists.
In addition to the alleged killing of Belmoktar, Ngobongue said that Chad's military had also nabbed 60 of the jihadists' cars, electronic equipment and weapons. "The raid is still ongoing," he said.