LOS ANGELES - A gunman removed a semi-automatic rifle from a bag at a Los Angeles International Airport security checkpoint Friday morning and opened fire -- killing a Transportation Security Administration employee and wounding three others -- before continuing to fire rounds inside the terminal as travelers sought cover, according to airport police.
Federal officials identified the alleged gunman Friday afternoon as 23-year-old Paul Ciancia, of Los Angeles, NBC News reported.
The "lone gunman" entered the screening area in the Tom Bradley International Terminal and opened fire before he was taken into custody after an officer-involved shooting, said Patrick Gannon, the chief of police at LAX. Witnesses described seeing shell casings, broken glass and blood on the ground in the terminal.
"He walked to Terminal 3, pulled an assault rifle out of a bag and opened fire in the terminal," Gannon said. "He went into the screening area, past screeners and continued shooting into the airport itself."
During a mid-day news conference, authorities did not confirm reports that the gunman was an off-duty or former TSA employee. In a statement released Friday afternoon the TSA said "multiple" officers were shot.
"Earlier this morning, a shooting occurred at Terminal 3 at Los Angeles International Airport," according to the statement. "Multiple Transportation Security Officers (TSOs) were shot, one fatally. Additional details will be addressed by the FBI and local law enforcement who are investigating the shooting."
FBI officials said the agency will "investigate the shooting and the motivation behind it."
"Joint investigators have neither ruled out terrorism, nor ruled it in," according to an FBI statement.
A spokesperson for UCLA Medical Center confirmed that one victim was hospitalized in critical condition and two were in fair condition at mid-day. It was "not clear" whether the critical patient was the gunman, Dr. Lynne McCullough said at a news conference.
The Los Angeles Fire Department transported six victims to hospitals. It was not clear whether the TSA agents and the gunman were among those transports.
The 9 a.m. PT shooting Friday morning prompted evacuations, street closures and a ground-stop order for all incoming flights at the nation's third-largest airport. Several travelers told NBC4 they heard gunfire in the terminal.
"We were just standing there and someone started shooting," witness Nick Pugh said. "I heard a total of maybe eight or 10 shots fired."
Pugh said he saw a man believed to be the gunman being chased by officers, but authorities have not confirmed that subject was involved in the shooting. Several people were questioned by law enforcement agents as they searched the terminal.
A camera positioned above the upper level road at LAX showed travelers running from an exit at the Tom Bradley Terminal, where passengers depart and arrive for international flights. Paramedics and other public safety personnel helped travelers, some in wheelchairs, to a triage area established outside the terminal.
"People freaked out," said witness Tim Daley, who reported hearing 15 rounds. "No one knew what to do."
Luke Love, a witness in Terminal 3, said he heard two loud bangs while he was taking his shoes off at security and saw a gunman dressed in all black walking up stairs with what Love described as an assault rifle.
Love, his mother and 10 other people were corralled into a room with the lights off and a copy machine blocking the door when he heard more shots, Love said.
LAPD issued a tactical alert, meaning all personnel will remain on duty until the situation has been resolved.
Roads near the airport are closed for the investigation, which is likely to continue into Friday evening. Some travelers got out of their vehicles and began walking to the airport with their luggage.
As incoming flights landed during the shooting investigation, they were subject to a ground-stop order.
At least two flights were diverted to Ontario International Airport, located east of Los Angeles.
The shooting comes more than 10 years after a gunman walked up to a ticket counter for Israel's national airline, El Al, at LAX, killing two and wounding four in a July 4 terrorist attack.
President Barack Obama was briefed on the situation, according to authorities.