Some 800,000 U.S. service members served in Afghanistan following the U.S.-led invasion triggered by the Sept. 11, 2001, attack on the U.S. by Afghanistan-based al Qaeda.
Multiple US officials continue to warn of possible Daesh attacks against the United States - the latest being Michael McCaul, Chairman of the Foreign Affairs Committee
McCaul noted that 26 August 2021 was the deadliest day for the United States in Afghanistan in over a decade.