Duffie Dixon, WXIA-TV, Atlanta

and John Bacon, USA TODAY

ATLANTA — A suspicious package brought chaos to Hartsfield-Jackson Atlanta International Airport on Wednesday as scores of travelers raced for the exits when authorities ordered the evacuation of a domestic terminal.

The brief evacuation was ordered after a dog trained to detect explosives was drawn to the package. The incident came one day after Mayor Kasim Reed announced security measures were "heightened" at the airport and other locations following a deadly terror attack at an airport in Belgium.

Greg Embry said he was waiting for a flight to Chicago when he saw people running down the concourse followed by Transportation Security Administration agents who ordered everyone to leave the terminal.

"After what happened yesterday (in Belgium), you think it's not going to happen here," Embry told WXIA-TV. "And then you have something like that taking place and you are running out and everybody is scared. ... It was a pretty strange experience to go through."

Video posted on Twitter from Hartsfield appeared to show people scrambling to exit the terminal. Some social media posts mentioned a "shooting," which was quickly denied by Atlanta police.

"Out of an abundance of caution, APD is investigating a suspicious package and has evacuated the public areas of the domestic terminal," airport officials tweeted. Minutes later, the airport tweeted: "The incident has been cleared and people are returning to the atrium."

Added Atlanta police: "There is no active shooter at the airport. A suspicious package has been cleared. ALL is OK!"

Flight operations returned to normal, officials said. Airport officials did not immediately return a call for comment.

On Tuesday, an attack at Brussels Airport left at least 11 people dead and scores injured. Authorities in Belgium determined the airport blast and one at a metro stop in the city that killed an additional 20 people were terrorist attacks. The Islamic State claimed responsibility.

Atlanta was among scores of cities across the nation and around the world that tightened security at airports, transportation hubs and other locations after the attack.

Denver had a scare Tuesday similar to Atlanta's false alarm. A bomb-sniffing dog's reaction to packages left at a ticket counter prompted authorities to evacuate a section of the main terminal of Denver International Airport.

That "suspicious packages" contained jars of oils and spices belonging to a Vietnamese family traveling home, airport officials said.