(CNN) -- One of al Qaeda's most influential figures in North Africa has been killed by French and Chadian forces, a U.S. official said Friday. French military sources had earlier said that Abdelhamid Abou Zeid, a deputy leader of al Qaeda in the Islamic Maghreb, was killed in an airstrike in Mali late last month. Abou Zeid was one of the group's most ruthless commanders, having seized at least a dozen foreigners for ransom. At least two have been killed; several French citizens remain captive. "He was a senior influential member of AQIM, and his death represents a significant blow to AQIM's efforts to use West Africa, and Mali in particular, as a safe haven," the official told CNN.
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NEW: U.S. official confirms death of Abdelhamid Abou Zeid
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The al Qaeda figure was killed in French airstrike, French military sources have said
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The deputy leader of al Qaeda in the Islamic Maghreb and his fighters were in northern Mali
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He had a reputation for brutality
Abou Zeid's death casts further uncertainty over the fate of the @placeholder hostages his group is still believed to hold.