Canberra Airport has been evacuated and planes have been grounded after a gunman fired shots near the check-in security screening area of the terminal.
Canberra, Australia. Photo: 123RF
ACT police took the man into custody and said a firearm had been recovered.
No one was injured during the incident.
ACT Policing Detective Acting Superintendent Dave Craft said the man entered the airport about 1:30pm and sat near the glass windows of the departures check-in area.
"After approximately five minutes this male has removed the firearm from his possession and let off approximately five rounds," he said.
"From what I can see from the crime scene, the male has let the shots off at the glass within the terminal.
"There were no shots directed at people ... customers or staff."
Three bullet holes can be seen in the glass windows of the departures hall.
Detective Acting Superintendent Craft said police believed the man acted alone and that there was no ongoing threat to the community.
"We have no idea of any motivation," he said.
"At this stage, it is our understanding the male arrived at the airport and did not go through any flight screening process."
ABC reporter Lily Thomson heard the shots and realised something was wrong when people started screaming "run".
"I saw this grandma with a baby and the fear in her face and I knew it was something serious," she said.
"So we all ran and I stayed with that grandma and her baby and hid behind an information desk. We stayed there for a couple of minutes until security told us to evacuate out to the car park.
"Everyone was hiding behind chairs and people were running.
"It was terrifying. We didn't know what was going on. The look on people's faces was quite terrifying."
The airport is still locked down and about five planes remain on the tarmac as Australian Federal Police continue to sweep the entire terminal and interview witnesses.
Detective Acting Superintendent Craft said police were working closely with airport staff and airlines to reopen the airport as soon as possible.
"Police have processed the crime scene and are looking to secure the area to enable passengers that are on arriving flights to exit the airport," he said.
"I just need to reassure people that the airport is safe, that ACT Policing have responded and there is no ongoing threat to the community or to passengers who are arriving and departing."
Canberra Airport said it was working with police and airlines to recommence flights this afternoon.
The airport said some flights had been cancelled or rescheduled and it advised travellers to check with their airline.
- ABC