"We're fortunate that when the firearm went off, nobody was seriously injured," Spinden said.

Three people suffered non-life-threatening injuries, the TSA said in a statement. Atlanta police had previously said no injuries were reported.

According to a source familiar with the situation, the injured were not shot but instead hurt during the evacuation. All of the injured were adults, the source said, and two were transported to the hospital. The discharged round went into the property of the person who brought the weapon, the source said.

The individual whose weapon was discharged was identified as 42-year-old Kenny Wells, according to Atlanta Police Department Airport Precinct Commander Reginald L. Moorman.

"We have taken out warrants for carrying concealed a weapon at a commercial airport, possession of a firearm by a convicted felon, discharging a firearm and reckless conduct," Moorman said. "We are actively pursuing this individual."

Airports spokesperson Andrew Gobeil characterized the discharge as accidental and said the loud noise created a "sense of chaos."

Airport officials and Atlanta Police know who the individual is, Gobeil told CNN's Jim Acosta, because the incident occurred while the passenger was being screened.

Erika Zeidler, who was traveling from Atlanta to Anchorage, Alaska, said she was sitting in a restaurant in Concourse T when people began running down the hallway.

"We thought they were late for a flight, and then more and more people started running," she told Acosta. "There was some screaming and then somebody stopped and said, 'There's a shooter, you need to go.'"

An investigation into the incident remains ongoing, Gobeil said.

In the meantime, there is no danger to passengers or employees, airport officials said on Twitter. Officials gave an "all-clear," and the airport was resuming normal operations.

A ground stop was called for the airport for all departing flights, per the Federal Aviation Administration, but was soon lifted.

Details about the weapon or circumstances surrounding the accidental discharge have not been made available.

The FBI and the ATF are "providing investigative assistance" to the Atlanta police, according to a spokesperson for the ATF. The White House is also "monitoring" the incident, a White House official said, referring questions to local law enforcement.

The shooting scare comes as the Thanksgiving travel period is getting underway. On Friday, TSA screened more than 2.2 million airport travelers across the country -- the highest checkpoint volume for a single day since the pandemic began, according to a TSA spokesperson.

Witnesses recount chaos after scare

Witnesses described confusion and disarray as panic erupted in one of the world's busiest airports.

Zeidler and others took shelter in a TGI Fridays restaurant, she said. Photos she shared on Twitter showed a crowd of people standing on the tarmac beneath a jetway as the incident unfolded.

Video posted on Twitter by Haşmet Asilkan showed people running out of the airport, telling others of a shooting that had taken place inside. Another video shared by Stephoń Stafford -- who said he was about to go through security with his child -- showed disorder inside, with a number of stanchions knocked over where people had previously been waiting in line.

Greg Romero had just gotten off a flight from Salt Lake City when he heard there was an emergency, he told CNN's Fredricka Whitfield. Airport personnel "shut off all the escalators and cut off all passengers and turned off the tram," said Romero, the father-in-law of CNN correspondent Nadia Romero.

"Right now airport personnel is doing a really good job keeping everybody calm," he added.

A few travelers were "a little bit panicked but more frustrated," Romero said. "They're trying to catch flights, to get out of the airport. For the most part, people are just lined up against the walls."