WASHINGTON (AP) — President Barack Obama says authorities will get to the bottom of details surrounding Saturday's deadly shooting in Arizona although the killer's motives are not immediately known.

A somber-looking Obama faced cameras in the White House and deplored the deaths of a federal judge, a nine-year-old girl and at least three other people in the shootings outside a Tucson grocery store. He called congresswoman Gabrielle Giffords a friend and said she is battling for her life.

The president said authorities don't know what provoked the shootings. He said there will be a comprehensive investigation and "we are going to get to the bottom of this."