WASHINGTON, Nov 14 (Reuters) - The U.S. military launched an air strike targeting the Islamic State's leader in Libya, U.S. officials told Reuters on Saturday, adding two F-15 aircraft were used in the attack.

Four years after the overthrow of Muammar Gaddafi, Islamic State has steadily grown in Libya's chaos, controlling the city of Sirte, and worrying Western governments who fear it can only become stronger. (Reporting by Phil Stewart; Editing by Chizu Nomiyama)

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