LOS ANGELES (AP) -- A man pulled a semi-automatic rifle from a bag and shot his way past a security checkpoint at Los Angeles International Airport on Friday, killing a federal security officer and wounding at two others in an attack that disrupted more than 700 flights across the U.S., authorities said.

Officials said the gunman, who was wounded in a shootout with police and taken into custody, targeted Transportation Security Administration agents, who handle security checks at U.S. airports.

 The FBI and Los Angeles Airport Police identified the suspected gunman as Paul Ciancia, 23, of New Jersey.

A law enforcement official, speaking on condition of anonymity because the official was not authorized to discuss the investigation publicly, said Ciancia was wearing fatigues and carrying a bag containing a handwritten note that said he wanted to kill TSA employees and "pigs."  The official said the rant refers to how Ciancia believed his constitutional rights were being violated by TSA searches and that he's a "pissed-off patriot" upset at former Department of Homeland Security Secretary Janet Napolitano.

Ciancia had at least five full 30-round magazines on him, said the official, who was briefed on the investigation. The official also said Ciancia was shot in the mouth and leg by two airport police officers.

Officials told a news conference they saw no further threat Friday 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 Friday 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 he called Los Angeles police, which sent a patrol car to Ciancia's apartment. Two roommates there said they had seen him 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 travelers 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.

The TSA identified the 39-year-old officer as Gerardo I. Hernandez and said he was the first officer killed in the line of duty in the agency's 12-year history.

The agency was founded in the aftermath of the Sept. 11, 2001 terrorist attacks. J. David Cox Sr., national president of the AFGE, said the officer was one of those stationed throughout the airport looking for suspicious behavior.

Initially, Cox said at least three other TSA officers were wounded. Their conditions were not disclosed. Later in the day, the TSA said two other officers were injured.

The Los Angeles Fire Department revised its total number of victims taken to the hospital from six to five, saying one had been double counted. Those numbers included the gunman, the slain TSA officer and one person who broke their ankle.

Terminal 3 is home to Virgin America, AirTran, Horizon Air, JetBlue, Virgin Australia and other airlines. It remained closed Friday evening.

The Federal Aviation Administration for hours grounded flights that had not yet departed for LAX. Airport officials said 746 flights nationwide were affected by the incident.

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.

It was not the first shooting at LAX. On July 4, 2002, a limousine driver opened fire at the airport's El Al ticket counter, killing an airline employee and a person who was dropping off a friend at the terminal. Police killed the man.