WASHINGTON - President Barack Obama is mourning what he calls "yet another mass shooting" in the United States that took the life of what he says were American patriots.
Obama promised to make sure, quote, "whoever carried out this cowardly act is held responsible."
Authorities said at least 12 people were killed in a shooting rampage Monday at the Washington Navy Yard about 3 1/2 miles from the White House.
Obama said the victims were "courageous Americans" who knew about the risks of serving overseas, but wouldn't have expected such "unimaginable violence" at home.
Obama later telephoned Navy Secretary Ray Mabus to express his condolences and FBI Director James Comey to commend the agency's response. He also ordered flags on federal property to be flown at half-staff through Friday.