A 26-year-old military veteran is in federal custody and investigators are searching for a motive after a shooting at the Fort Lauderdale, Fla., airport left five people dead and eight wounded — with many more injured in the chaos that followed the attack.

Authorities said they are looking at all angles as they investigate the shooting near the baggage area inside Terminal 2, which serves Delta Air Lines and Air Canada.

The airport suspended operations as law enforcement authorities rushed to the scene, and emergency medical workers treated people on the tarmac.

Law enforcement officials speaking Friday night said Esteban Santiago was in custody in connection with the case. He was unharmed when taken into custody and law enforcement fired no shots.

Santiago served in Iraq with the National Guard before being discharged. He has been interviewed by the FBI and local police, officials said.

FBI gives an update on Fort Lauderdale airport shooting6:41

Neither local nor federal officials would speculate on motives for the shooting, saying only that every possibility, including terrorism, was being considered.

George Piro, special investigator in charge of the Miami FBI who spoke Friday, said that the accused will be charged federally and a first court appearance is expected Monday.

He also confirmed a report from unnamed sources that Santiago had walked into an FBI office in Anchorage, Alaska, in November. The official said Friday that when he walked into the Alaska office, Santiago was showing erratic behaviour but said he didn't intend to harm anyone. FBI agents contacted local police, who in turn took him to medical facility for a mental health assessment. 

Jesse Davis, the chief of police at Ted Stevens Anchorage International Airport in Alaska, told The Associated Press that Santiago flew out of the city on Thursday at 9:52 p.m. local time on a Delta flight, and that a firearm was his only piece of checked luggage. He said Santiago flew from Anchorage to Minneapolis-St. Paul and on to Fort Lauderdale.

The brother of Esteban Santiago said Esteban had been receiving psychological treatment while living in Alaska.​​

Bryan Santiago told The Associated Press that his family got a call in recent months from Esteban Santiago's girlfriend alerting them to the situation. He said he didn't know what his brother was being treated for and that they never talked about it over the phone.

Airport Shooting Florida

Police waiting to escort employees and passengers walk outside Terminal 2 at the Fort Lauderdale-Hollywood International Airport on Friday. (David Santiago/El Nuevo Herald via Associated Press)

A spokeswoman for the Alaska National Guard said Santiago served as a combat engineer in the guard before his discharge for "unsatisfactory performance."

Lt.-Col. Candis Olmstead would not elaborate on his discharge, but the Pentagon said he'd gone AWOL several times and was demoted and discharged.

'There is no Canadian connection'

Chip LaMarca, a Broward County commissioner who was briefed on the airport shooting by the Broward Sheriff's Office, had initially told The Associated Press that the shooter had arrived in Fort Lauderdale with a gun aboard a Canadian flight.

However, Christine Constantin, spokeswoman at the Canadian Embassy in Washington, said in a statement, "There is no Canadian connection."

"We confirm that the shooter did not come from a Canadian flight, or from Canada," she said.

Global Affairs Canada said it was monitoring the situation and urged Canadians in the area to contact the Consulate General of Canada in Miami in the event of an emergency.

Canada's Minister of Foreign Affairs Stéphane Dion on Twitter offered his condolences to the families and friends of those killed and wished those injured a speedy recovery.

Airport hopes to reopen tomorrow

An official said Friday night that it's hoped the airport will be operational Saturday by at 5 a.m. ET. They urged travellers to check with their airlines and to follow the airport's social media accounts for more detailed information.

After the shooting, Delta Air Lines said in a statement, "Preliminary reports indicate that all Delta employees are safe and accounted for."

Delta CEO Ed Bastian said he extends his thoughts and prayers to "those involved in the tragic events today."

On Twitter, Air Canada said it was "deeply saddened by the tragic event" and that all of its customers and staff at the airport were accounted for and safe.

The attack exposed a weak point in airport security: While travelers have to take off their shoes, put their carry-on luggage through X-ray machines and pass through metal detectors to reach the gates, many other sections of airports, such as ticket counters and baggage claim areas, are more lightly secured and more vulnerable to attack.

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. 

'He was standing there shooting somebody'

Russel Crooks, a Canadian at the airport, had just returned from a cruise with his partner when the gunman opened fire in Terminal 2.

"We jumped up and I realized that it was either a bomb or a gunshot and we ran about five feet away to a desk, a kiosk information booth, and sort of pulled under there," he told CBC.

"He was standing there shooting somebody and I looked away because, quite honestly, I thought that he was going to turn left towards us and he would have seen the people behind this tiny, tiny desk and we were just right there."

Terminal 2 of Fort Lauderdale-Hollywood International Airport

The shooting took place in the baggage claim area of Terminal 2 of Fort Lauderdale-Hollywood International Airport. (CBC)

Another witness, John Kaneklides, was in Terminal 2 when the shots broke out and also hid under a kiosk before rushing onto the tarmac when doors opened.

"Passengers started rushing out the door and so we were just kind of climbing on all fours as fast as we could to exit the departure area and get on the tarmac," he told CBC News.

Kaneklides said he was taken by authorities to Terminal 4, where he said there is "an air of panic in the room."

He also said the airport kept passengers "in the dark" about what was going on.

"In fact, we would have no idea what happened in Terminal 2 if it were not for Twitter and the news," Kaneklides said.

Florida airport witness video1:30

With files from CBC News