This is a breaking news story. Check back for updates.

UPDATE 3:50 p.m. EDT: A 40-year-old victim of the LAX shooting has died, according to the L.A. County coroner.

UPDATE 3:18 p.m. EDT: Pete Williams of NBC News said a "series of federal officials" don't believe the gunman was a TSA employee as had been reported by other media outlets. "All we know is this is a man in his early 20s who is a U.S. citizen," Williams said. The suspect is not believed to be from the Los Angeles area; an out-of-state ID was recovered, according to Williams. He is in critical condition at UCLA Medical Center, and it's unlikely that investigators have been able to question him.

UPDATE 3:03 p.m. EDT: Authorities said they would not be speaking about the identity of the suspect.

"I'm going to give you very few facts today," said FBI Special Agent In Charge David Bowdich. He added that authorities "don't see any additional threats at the airport."

UPDATE 2:59 p.m. EDT: Los Angeles World Airports Executive Director Gina Marie Lindsey said LAX is still accepting incoming flights but at less than half of its normal arrival rate. Los Angeles Fire Department Interim Chief Jim Featherstone said seven patients were treated by the LAFD and 100 firefighters responded to the scene.

UPDATE 2:56 p.m. EDT: LAX Police Chief Patrick Gannon says the shooter is believed to be the only gunman in the incident. "We believe at this point that there was a lone shooter," he said. He added that the gunman was taken into custody, disputing reports that the shooter was killed. He said the incident started around 9:20 a.m. local time, when the gunman went into Terminal 3 at LAX, pulled an assault rifle out of a bag and opened fire in the terminal. The suspect then went past airport screeners, at which point LAX police responded. Police tracked the suspect through the airport and opened fire on him. He was then taken into custody.

UPDATE 2:54 p.m. EDT: Los Angeles Mayor Eric Garcetti said law enforcement believe the incident is over. "We believe this to be a static situation now," he told a news conference.

UPDATE 2:46 p.m. EDT: Authorities are still working on the identity of the gunman, but he's been described as a U.S. citizen in his early 20s, according to NBC News.

UPDATE 2:38 p.m. EDT: All of the victims in the LAX shooting were TSA agents, according to NBC News. Meanwhile, a photo has been circulating on Twitter supposedly showing the rifle used in the shooting:

UPDATE 2:26 p.m. EDT: A law enforcement official told NBC Los Angeles that officers are sweeping Terminal 3 and a bomb squad is checking dropped bags "in an abundance of caution." The official couldn't confirm if there were multiple suspects, but said one suspect was taken into custody by LAX police. He said it will be at least a couple of hours before the bomb squad finishes its sweep.

UPDATE 2:09 p.m. EDT: The gunman was an off-duty TSA agent, a source told CBS News, according to Charlie Kaye. KTLA reported that the shooter was yelling in English while he opened fire.

UPDATE 2:01 p.m. EDT: According to NBC Los Angeles, a TSA agent was killed in the shooting. Another security agent was wounded.

UPDATE 1:47 p.m. EDT: CBS Los Angeles is reporting that one of the victims may have been killed.

UPDATE 1:37 p.m. EDT: A ground stop is in effect at LAX.

UPDATE 1:24 p.m. EDT: There may have been more than one suspect in the LAX shooting, according to John Miller of CBS. The suspect or suspects wore camouflage and reportedly targeted a TSA employee. At least three people were wounded.

UPDATE 1:04 p.m. EDT: The Los Angeles Times is reporting that Terminal 2 and Terminal 3 were evacuated shortly after the shooting. Eyewitness Robert Perez described the scene for CBS Los Angeles.

"I heard popping and everybody dropped to the ground,” he said.

Another witness, Nick Pugh, spoke to NBC Los Angeles.

"We were just standing there and someone started shooting," he said. "I heard a total of maybe eight or 10 shots fired."

UPDATE 12:59 p.m. EDT: The gunman opened fire at a security checkpoint, NBC Los Angeles reports. A TSA employee was wounded, according to the station.

UPDATE 12:53 p.m. EDT: Authorities have confirmed to CBS Los Angeles and the Los Angeles Times that a shooting took place at LAX. CBS LA says the shooter was carrying a rifle and was "shot and secured" by law enforcement.

Original story:

A terminal at Los Angeles International Airport was evacuated amid reports of a possible shooting Friday morning.

CBS Los Angeles reported that an “incident” occurred at LAX, citing police. Some Twitter users reported a shooting at the airport’s Terminal 3, but those reports have not been verified.

Mythbuster host Tory Belleci tweeted the following photo of passengers being evacuated from LAX: