France confirmed "with certainty" on Saturday that Abdelhamid Abou Zeid, one of al Qaeda's most feared commanders in Africa, had been killed in Mali last month in a French-led offensive.
The death of Abou Zeid, who raised millions of dollars kidnapping Western hostages, marks a heavy blow to al Qaeda's North African wing AQIM and to Islamist rebels battling French-led forces in northern Mali's Adrar des Ifoghas mountains.
The death of the ruthless commander - the trusted lieutenant of AQIM's elusive leader Abdelmalek Droukdel - was a major victory in France's nine-week-old campaign to drive al Qaeda-linked Islamists from Mali's desert north.
It raises questions, however, about the fate of several French hostages believed to be held by Abou Zeid's branch of AQIM.
"The president of the French Republic confirms with certainty the death of Abdelhamid Abou Zeid after an offensive by the French army in the Adrar des Ifoghas," the Elysee presidential palace said.
Previously France had said only that Abou Zeid was "probably" dead. Chad, whose troops are fighting alongside French forces in the Adrar des Ifoghas, announced in early March that the Algerian smuggler-turned-Islamist had been killed.
France had been awaiting the results of DNA testing - which finally confirmed Zeid's identity - before making an official announcement, a diplomatic source told Reuters.
French forces launched a ground and air campaign in Mali on Jan. 11, warning that the Islamist enclave in northern Mali controlled by AQIM and its allies presented a threat to international security.
The Islamists had hijacked a Tuareg rebellion which had driven Mali's demoralised army from the northern two-thirds of the landlocked country in April last year.
While the French-led offensive has pushed Islamists out of northern towns and remote mountain bases, militants have hit back with several suicide bombings in government-held areas.
A spokesman for AQIM said earlier this week it had beheaded a French hostage in retaliation for Paris' intervention, Mauritania's ANI news agency reported - a worrying development for France and its 14 hostages held in West Africa.
Abou Zeid is believed to have killed British hostage Edwin Dyer in 2009 and 78-year-old Frenchman Michel Germaneau in 2010.
Confirmation of his death will turn attention to the fate of fellow al Qaeda commander Mokhtar Belmokhtar, who was also reported dead by Chad.
Saturday's statement made no mention of Belmokhtar, the mastermind of a mass hostage-taking in January at the In Amenas gas plant in the Algerian desert in which around 60 people were killed.
Edouard Guillaud, the head of France's joint chiefs of staff, said this month he was "extremely cautious" about reports of Belmokhtar's death, noting that some militant websites had said the al Qaeda commander, nicknamed 'the uncatchable', was still at large.
(Reporting by Lionel Laurent and Elizabeth Pineau; Editing by Daniel Flynn and Stephen Powell)