UPDATED 3.16PM: A New Zealand traveller was among those paralysed with fear after a gunman opened fire at the Fort Lauderdale airport today.

Caroline Gaisford, 35, of Auckland's Meadowbank, arrived at the Fort Lauderdale-Hollywood Airport about 1pm and was checking in when she heard the first gunshot.

She said it was a chaotic situation, with kids screaming and some people losing track of their children.

Fairfax reported Ms Gaisford and her American friend hid for another two hours before instructions came over the loudspeakers saying stay calm.

She was to have boarded a flight to San Francisco that afternoon for an overnight stay before flying back to New Zealand.

An arriving airline passenger with a gun in his checked luggage opened fire in the baggage claim area at the airport, killing five people and wounding eight before throwing his weapon down and lying spread-eagle on the ground, authorities and witnesses said.

The gunman - identified by authorities as 26-year-old Esteban Santiago, an Army National Guard veteran who served in Iraq but was demoted and discharged last year for unsatisfactory performance - was immediately taken into custody. His brother said he had been receiving psychological treatment recently.

One witness said the attacker gunned down his victims without a word and kept shooting until he ran out of ammunition, sending panicked travellers running out of the terminal and spilling onto the tarmac, baggage in hand.

Others crouched behind cars or anything else they could find to shield themselves as police and paramedics rushed in to help the wounded and establish whether there were any other gunmen. The airport was shut down.

"People started kind of screaming and trying to get out of any door they could or hide under the chairs," a witness, Mark Lea, told MSNBC. "He just kind of continued coming in, just randomly shooting at people, no rhyme or reason to it."

Authorities said the motive was under investigation.

"This could well be someone who is mentally deranged, or in fact it could be someone who had a much more sinister motive that we have to worry about every day, and that is terrorism," said Sen. Bill Nelson of Florida. "We can't conclude that."

President Barack Obama was briefed by his Homeland Security adviser, the White House said.

It is legal for airline passengers to travel with guns and ammunition as long as the firearms are put in a checked bag - not a carry-on - and are unloaded and locked in a hard-sided container. Guns must be declared to the airline at check-in.

Santiago arrived in Fort Lauderdale after taking off from his hometown of Anchorage, Alaska, aboard a Delta flight Thursday night, checking only one piece of luggage - his gun, said Jesse Davis, police chief at the Anchorage airport.

At Fort Lauderdale, "after he claimed his bag, he went into the bathroom and loaded the gun and started shooting. We don't know why," said Chip LaMarca, a Broward County commissioner who was briefed by investigators.

The attack exposed another weak point in airport security: While travellers have to take off their shoes, put their carry-on luggage through X-ray machines and pass through metal detectors and full-body scanners to reach the gates, many sections of airports are more lightly secured and more vulnerable to attack.

In 2013, a gunman with a grudge against the Transportation Security Administration shot and killed one of the agency's screeners and wounded three others during a rampage at Los Angeles International Airport.

Last November, an airline worker was shot and killed near an employee parking lot at Oklahoma City's airport, and in 2015 a machete-wielding man was shot to death after he attacked federal security officers at the New Orleans airport.

In the Fort Lauderdale attack, Lea said the gunman said nothing as he "went up and down the carousels of the baggage claim, shooting through luggage to get at people that were hiding." The killer had a handgun and went through about three magazines before running out of ammunition, Lea said.

"He threw the gun down and laid spread-eagle on the ground until the officer came up to him," Lea said.

Sheriff Scott Israel said five people were killed and eight were wounded. Their condition was not disclosed. He said the gunman was arrested unharmed, with no law enforcement officers firing any shots, and was being questioned by the FBI.

The airport suspended operations as law enforcement authorities rushed to the scene and emergency medical workers treated the bleeding victims. Fort Lauderdale-bound flights already in the air were delayed or diverted, and those that had yet to take off from the airport were held on the ground.

At least one person appeared to be lying in a pool of blood with a head wound.

Santiago's brother, Bryan, told The Associated Press that his brother had been receiving psychological treatment in Alaska. He said Santiago's girlfriend alerted the family to the situation in recent months.

Bryan Santiago said that he didn't know what his brother was being treated for and that they never talked about it over the telephone.

He said Esteban Santiago was born in New Jersey but moved to Puerto Rico when he was 2. He was deployed to Iraq in 2010 and spent a year there with the 130th Engineer Battalion, according to Puerto Rico National Guard spokesman Maj. Paul Dahlen. He later joined the Alaska National Guard.

The Pentagon said Santiago had gone AWOL several times during his stint with the Alaska National Guard and was demoted - from specialist to private first class - and given a general discharge, which is lower than an honourable discharge.

At the Fort Lauderdale airport, John Schilcher told Fox News said he came up to the baggage claim and heard the first gunshot as he picked up his bag off a carousel.

"The person next to me fell to the ground and then I started hearing other pops. And as this happened, other people started falling and you could hear it and smell it, and people on either side of me were going down and I just dropped to the ground," said Schilcher, who was there with his wife and mother-in-law. "The firing just went on and on."

"I was down on the floor. When we finally looked up there was a policeman standing over me," he said. "That's when I assumed it was safe."

 

 

Other deadly attacks at US airports

• November 16, 2016: A Southwest Airlines worker was shot and killed near an employee parking lot at Oklahoma City's airport. Police said the man who shot him was likely retaliating after losing his own job with the airline.

• March 21, 2015: A machete-wielding man attacked federal transportation security officers, slightly injuring one, at New Orleans' international airport and was shot to death. Authorities later said he also was carrying a bag loaded with Molotov cocktails.

• November 1, 2013: A gunman with a grudge against the Transportation Security Administration shot and killed one of the agency's screeners and wounded three other people during a rampage at Los Angeles International Airport. He was sentenced to life plus 60 years in prison for murder and other crimes.

• July 4, 2002: An Egyptian national from Irvine, California, opened fire at an El Al ticket counter at Los Angeles International Airport, killing an airline employee and a diamond importer, and wounding four others. He was shot dead by a security guard.

• May 22, 2002: A former Marine killed a San Diego woman in the ticket area of the Louis Armstrong International Airport in New Orleans with a shotgun he had concealed inside a tube container. He was later found not guilty by reason of insanity.