Cellphone video posted on social media showed victims on the floor next to a carousel, with people on their knees attempting to provide aid. At least two victims had pools of blood from apparent head wounds.

The shooter was unharmed as law enforcement officers never fired a shot, Israel said, adding it was too early to assign a motive.

“At this point, it looks like he acted alone,” Israel said.

Nonetheless, he said “this scene is considered fluid and active” as police searched the airport.

The Florida attack was the latest in a series of mass shootings that have plagued the United States in recent years, some inspired by militants with an extreme view of Islam, others who are loners or mentally disturbed who have easy access to weapons under US gun laws.

The shooter was identified as Esteban Santiago, 26, and had a US military identification, according to a spokesman for US Senator Bill Nelson of Florida, who spoke with officials at the Transportation Security Administration.

A 26-year-old by the name of Esteban Santiago was honourably discharged from the Army National Guard last year and served in Iraq, a US official said, speaking on condition of anonymity.

The shooter, who wore a “Star Wars” T-shirt, said nothing as he fired, witnesses told MSNBC. He appeared to use a 9 mm handgun, which he tossed aside upon running out of ammunition, surrendering to police, MSNBC reported.

Security officials corralled passengers into a number of areas, including underneath jetways and at least one open space on the runway apron, according to images on cable news networks.

Ari Fleischer, a former press secretary for US President George W. Bush, said on Twitter that shots were fired and “everyone is running.”

“All seems calm now but the police aren’t letting anyone out of the airport - at least not the area where I am,” Fleischer said.

About 90 minutes after the attack, panic broke out anew with passengers and police running frantically about at a separate terminal, but Israel said there were no other reports of shots being fired.

One person was injured trying to evacuate, which may have triggered the later panic, Israel said. Dozens of police sprinted back and forth with automatic weapons drawn, and one officer screamed “Get down, get down!” from a nearby parking garage, a Reuters reporter witnessed.

John Schlicher, who told MSNBC he saw the attack, described the shooter as a slender man who was “directly firing at us” while passengers waited for their bags.

“I put my head down and prayed,” Schlicher said, adding that his wife gave first aid to someone who had been shot in the head. His mother-in-law used her sweater to tend to another victim but it turned out that person was already dead, he said.

The shooter reloaded for another burst of shooting, Schlicher said, but could not say how many bullets were fired.

Mark Lea, another eyewitness, told MSNBC “there was no rhyme or reason to it.”

“He didn’t say anything, he was quiet the whole time, he didn’t yell anything,” Lea said.

The shooting took place at the Terminal 2 baggage claim, said a post on the airport’s Twitter account.

Fort Lauderdale-Hollywood International Airport is the second largest in South Florida, serving as an intercontinental gateway, with Miami International Airport known as the primary airport for international flights in the area.

Nearly two months ago a former Southwest Airlines worker killed an employee of the company at Oklahoma City’s airport in what police called a premeditated act.

The deadliest mass shooting in modern US history took place last June, when a gunman apparently inspired by Islamic State killed 53 people and wounded 49 at a gay nightclub in Orlando, Florida.

All services were temporarily suspended, the airport’s Twitter feed said.

Florida Governor Rick Scott was travelling to Fort Lauderdale to be briefed by law enforcement, his office said in a statement.

The FBI’s Miami office was “aware of the situation” and in contact with local authorities, a spokesman said in an email. No further information was immediately available.

Attackers have exploited security officials’ focus on preventing attacks on air planes rather than inside airports. In Western Europe and the United States, terminals are easily accessible public spaces.

But at Israel’s Ben Gurion Airport, widely seen as a model for security, private companies trained by the national security agency use bomb-detectors, profile passengers and question travellers under the watch of police at the airport’s entrance. That may just shift the target to another location at the airport, experts have said, however.