A man pulled a semi-automatic rifle from a bag and shot his way past a security checkpoint at Los Angeles International Airport, killing a federal security officer and wounding three other people.
Officials said the gunman, who was wounded in a shootout with police and taken into custody, targeted Transportation Security Administration agents.
A law enforcement official said the shooting suspect was Paul Ciancia, 23, from New Jersey. He was wearing fatigues and carrying a bag containing a handwritten note that said he "wanted to kill TSA and pigs," the official said, who was briefed on the investigation.
A second law enforcement official confirmed the identity, speaking on condition of anonymity because he was not authorized to discuss the investigation publicly.
Officials told a press conference they saw no further threat yesterday to the nation's third largest airport, which is a major gateway for flights to Asia, Australia and New Zealand.
A police chief in New Jersey said Ciancia's father called him yesterday saying another of his children had received a text message from Ciancia in reference to him taking his own life." Pennsville Chief Allen Cummings said Ciancia's father asked him for help in locating his son.
The chief said he called Los Angeles police, which sent a patrol car to Ciancia's apartment. Two roommates there said they had seen him on Thursday and that he was fine.
Los Angeles Airport Police Chief Patrick Gannon said the gunman entered Terminal 3, pulled an assault rifle from a bag and began shooting, then fired more shots at a screening checkpoint, where a security agent was checking passenger documents, before entering the secure area of the terminal.
Officers exchanged fire with the gunman and apprehended him. Police believe he was the only shooter, Gannon said.
"As you can imagine, a large amount of chaos took place in this entire incident," Gannon said.
Panicked travellers dropped to the ground. Those who had made it past security fled onto the tarmac or sought cover inside restaurants and lounges.
Xavier Savant, who was waiting in the security line where the shooting occurred, described it as a "Bam! Bam! Bam!" burst of gunfire.
Another witness, Brian Keech, said he heard "about a dozen gunshots."
Tim Kauffman, a spokesman for the American Federation of Government Employees, confirmed that a TSA officer was killed. He said the union's information came from their local officials in Los Angeles.
Union and TSA officials said the officer was the first ever killed in the line of duty. The agency was founded in the aftermath of the September 11, 2001 terrorist attacks. J. David Cox Sr., national president of the AFGE, said the officer was one of the officers stationed throughout the airport looking for suspicious behavior.
Six people were taken to the hospital, the Los Angeles Fire Department said. Ronald Reagan UCLA Medical Center said it received "three male victims from the LAX Airport shootings. One arrived in critical condition and two are listed in fair condition."
Terminal 3 is home to Virgin America, AirTran, Alaska Airlines, Horizon Air, JetBlue, Virgin Australia and other airlines.
Air traffic was affected nationwide. The Federal Aviation Administration grounded flights that had not yet departed for LAX.
Ben Rosen said he heard gunfire erupt and saw people start running in all directions and others crouching. He lay on the ground. Police, with their guns drawn, shouted, "This is not a drill, hands up."
"It was scary I've never experienced anything like this before," Rosen said.