From Breitbart News:

All vehicle and pedestrian traffic into and out of the airport has been limited. LAPD is doing a sweep of the arrival area of Terminal 3. One witness, Robert Perez, said that TSA agents shouted that a man had a gun in the terminal. “I heard popping and everybody dropped to the ground,” Perez said. Another witness reported a dozen shots fired. A Federal Aviation Authority map already shows flight slowdowns thanks to the incident; the FAA was put on a ground hold.