The shooting took place in Fort Lauderdale Airport in Florida.
A number of people are said to be injured. Three people have been shot dead, according to NBC.
Passengers and workers were evacuated on to the tarmac.
Terrified witnesses told how “everyone” started running as the gunman as the gunman open fire at the popular airport.
The drama unfolded in the baggage claim area, according to local reports.
Ari Fleischer, a former White House press secretary, tweeted: “I’m at the Ft. Lauderdale Airport. Shots have been fired. Everyone is running.”
“The police aren’t letting anyone out of the airport – at least not the area where I am.”
According to NBC the gunman is in custody. However unconfirmed reports say the suspect has been killed.
On social media site, Twitter Fort Lauderdale airport said there was an “ongoing incident” in the baggage claim area of terminal two.