Tim Kauffman, a spokesman for the American Federation of Government Employees in Washington, told the Associated Press that the victim who died was a Transportation Security Administration officer. He said the union's information came from its local officials in Los Angeles.
Law enforcement officials identified the suspect as 23-year-old Paul Ciancia.
Airport police chief Patrick Gannon said the gunman forced his way past a TSA checkpoint into the heart of LAX Terminal 3.
He said authorities believe the gunman acted alone.
Ciancia, a U.S. citizen, was shot in the face in the confrontation with police, a federal law enforcement official said. The official, who was not authorized to speak publicly, said the suspect had survived the shooting but his condition was not immediately known.
One TSA officer is the only person confirmed dead, the official said.
Gannon said the shooting began at 9:20 a.m. PT, when the suspect pulled an "assault rifle" out of a bag and began to open fire in LAX Terminal 3.
"He proceeded up to...