At least five people were shot dead Friday at one of South Florida's busiest airports, leading officials to close the facility and advise people to "shelter in place."
The gunfire happened at Fort Lauderdale-Hollywood International Airport Friday afternoon and also injured at least eight others, the Broward County Sheriff's Office said.
Law enforcement sources told NBC News they arrested one suspect after the shooting near the baggage claim area of Terminal 2, where Delta Air Lines operates.
Broward County Sheriff Scott Israel, in a 3:25 p.m. press briefing, said it appeared the man in custody worked alone, but law enforcement was methodically searching all terminals and parking areas to make sure there was no further threat.
"The scene is considered fluid and active," he said.
Israel said there were no shots fired elsewhere in the airport.
"The only gunshots fired at any time during this horrific incident happened downstairs at Terminal 2," he said.
The sheriff said the suspect was taken into custody uninjured and without incident. Officers never fired a shot.
Airport officials said all operations were halted and it's unclear when they would resume.
A sheriff's office spokeswoman told CBS the suspect is male. A witness told the network the shooter appeared to be in his early 20s, and walked into the airport without saying anything and began shooting.
Sen. Bill Nelson, D-Fla., told MSNBC the suspect was carrying a military ID and identified him as Esteban Santiago, 26. Israel declined to identify the suspect, nor did he offer any details about the weapon used.
Former White House Press Secretary Ari Fleischer under President George W. Bush was at the airport at the time of the shooting and tweeted about the incident.
"I'm at the Ft. Lauderdale Airport. Shots have been fired. Everyone is running," he tweeted shortly before 1 p.m.
About 15 minutes later he reported that "all seems calm now but police aren't letting anyone out of the airport -- at least not the area where I am."
MSNBC reported some passengers at the airport were being held on the tarmac before being evacuated. Around 2:30 p.m., police sent more passengers back to the tarmac from the baggage claim area, some running. It was unclear if there was a further threat to Terminal 2.
One witness in the baggage claim area at the time of the shooting, Mark Lea, 53, told NBC News he was dodging bullets and trying to help people move out of the way.
"At first we thought it was firecrackers," he said. "Everyone started screaming and running. The shooter made his way down through baggage claim. He had what looked like a 9mm and emptied his entire clip. People were trying to run."
Lea called the scene "surreal" and said people were tripping over each other trying to make a fast exit out of the door.
The FAA ordered a full ground stop on all flights at FLL, though some planes could be seen taking off from the airport after the shooting.
President-elect Donald Trump tweeted that he's "monitoring the terrible situation in Florida."
"Just spoke to Gov. [Rick] Scott. Thoughts and prayers for all. Stay safe!" he said.