Mattis Says Khashoggi Killing Could Destabilize Middle East

Defense secretary calls for ‘unwavering respect for human rights’ at conference in Bahrain

MANAMA, Bahrain—Defense Secretary Jim Mattis on Saturday said any role Saudi Arabia played in a journalist’s killing could destabilize the Persian Gulf region and beyond, leveling rare criticism at a military ally.

“With our collective interests in peace and unwavering respect for human rights in mind, the murder of Jamal Khashoggi in a diplomatic facility must concern us all,” Mr. Mattis told a group of Gulf security officials that included senior members of a Saudi delegation. “Failure of any nation to adhere to international...