UPDATE: Gunman kills TSA agent at LAX, injures 2 others

LOS ANGELES (AP) — A gunman armed with a semi-automatic rifle opened fire at Los Angeles International Airport today, killing a Transportation Security Administration employee and wounding two other people in an attack that frightened passengers and disrupted flights nationwide, officials said.

Los Angeles police Assistant Chief Earl Paysinger said the unidentified suspect, who was apparently injured after an exchange of gunfire with officers, was in custody.

Tim Kauffman, a spokesman for the American Federation of Government Employees in Washington, confirmed that a TSA officer was killed. Kauffman said the union's information comes from their local officials in Los Angeles.

Los Angeles Airport Police Chief Patrick Gannon said the gunman pulled what he described as an "assault rifle" from a bag and began firing. "As you can imagine, a large amount of chaos took place in this entire incident," he said.

Some passengers who already had cleared security rushed onto the tarmac to evacuate, while others were locked down in airport restaurants and lounges. The airport was being swept for precautionary measures and the bomb unit was on scene.

Air traffic was affected nationwide as the FAA grounded flights that had not yet departed for LAX.

Witness Brian Keech said he heard "about a dozen gunshots" from inside a security gate at the terminal, which has been evacuated.