FBI says it presumes base shooting was act of terrorism

Four people, including the suspect, are dead after a shooting at Naval Air Support in Pensacola. (Google Maps)

PESNACOLA, Fla. (AP) -- The FBI is confirming it is operating on the assumption that the deadly attack at the Pensacola, Florida, naval base by a Saudi flight students was an act of terrorism, while a U.S. official says the gunman had apparently gone on Twitter shortly before the shooting to blast U.S. support of Israel and accuse America of being anti-Muslim.

Investigators are also working to establish whether the killer, identified as 2nd Lt. Mohammed Alshamrani, 21, of the Royal Saudi Air Force, acted alone.

Alshamrani was killed in the attack at a classroom building Friday.