The IS group announced on Tuesday that one of its longest-serving and most prominent leaders, Abu Muhammad al-Adnani, was killed in Syria, depriving the organization of the man in charge of directing attacks overseas.
A U.S. defense official told Reuters the United States carried out an air strike in the Syrian town of al-Bab against a senior IS member. The official declined to disclose the target and said the operation was still being reviewed.
A senior Syrian rebel official had said earlier that Adnani was most probably killed in al-Bab in Aleppo province.
Adnani had been one of the last living senior members, along with self-appointed caliph Abu Bakr al-Baghdadi, that founded the group and stunned the Middle East by seizing huge tracts of Iraq and Syria in 2014.
As IS's spokesman, Adnani was its most visible member. As head of external operations, he was in charge of attacks overseas, including Europe, that have become an increasingly important tactic for the group as its core Iraqi and Syrian territory has been eroded by military losses.
Advances by Iraq's army and allied militia toward IS's most important possession of Mosul have put the group under new pressure at a moment when a U.S.-backed coalition has cut its Syrian holdings off from the Turkish border.
Those military setbacks have been accompanied by air strikes that have killed several of the group's leaders, undermining its organizational ability and dampening its morale.
