A gunman opened fire Friday inside Terminal 3 at Los Angeles International Airport, killing one Transportation Security Administration worker, while wounding as many as three others, NBC News reported.

The shooting forced travelers to evacuate the terminals causing major traffic, authorities and witnesses said. The lone gunman, Paul Anthony Ciancia, wounded after a gun battle with police, was in custody.

The shooting started at around 9:20 a.m, as Cianci pulled out an assault rifle from his bag and shot his way through security, Patrick Gannon, chief of the airport police told NBC News.  LAX is the sixth busiest airport in the world.

"We were just standing there in line and somebody started shooting," Nick Pugh, an eyewitness, told NBC Los Angeles.

"Federal that it was unclear whether the gunman was targeting the TSA or was trying to shoot his way through to get further into the airport," NBC News also reported.

The Federal Aviation Administration grounded flights at the airport, following the shooting, news reports said.

"There were helicopters overhead," said eyewitness Darren Lefkowitz, who flew in from Orlando, Florida just minutes after the shooting. "No one was sure what was happening. There were no announcements made."

Lefkowitz's flight landed in Terminal 5, but the mayhem occurred at Terminal 3.

Lefkowitz, a chief officer at Ding! Bikes in Casseberry, Florida, flew to Los Angeles for the Recumbent Cycle-Con convention in Pomona.

While not under direct threat, Lefkowitz realized walking rather than taking a taxi to the Enterprise Rental Car dealership nearby would be more prudent,

"All traffic was stopped and cabs were stuck in the road," Lefkowitz said, adding that, only through "rumors" from fellow travelers that a shooting had just taken place.