At least nine people were shot, including three fatally, and a suspect was in custody at the Fort Lauderdale-Hollywood International Airport in Florida on Friday.

“There is an ongoing incident in Terminal 2, Baggage Claim,” said a post on the airport’s Twitter account.

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 U.S. 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.

The airport says over 73,000 travelers pass through each day.

The Bureau of Alcohol, Tobacco, Firearms and Explosives said agents were going to the scene to help state and local authorities.

A law enforcement expert said authorities will try to determine who the suspect is and whether there are other plots afoot.

Fatal shootings at airports, where security is tight, are unusual.

In November 2016, a disgruntled former employee opened fire at the Will Rogers World Airport in Oklahoma City, killing a Southwest Airlines worker.