Since 2005, U.S. special operations forces have been conducting Flintlock joint military exercises in western Africa.
Top military leaders dispute Defense Secretary Jim Mattis on transgender troops serving openly.
Facing increased competition from Russia and China, the Air Force is pushing to develop experimental technologies for combat.
The Taliban denied involvement in the attack, which means it was likely carried out by a local Islamic State affiliate.
Syria has accelerated its military campaign to retake all remaining enclaves in the capital and surrounding areas.