Rocks smashed through a glass door at the Hyatt Hotel Canberra on Wednesday morning causing panic during a major defence industry conference as police searched for those responsible.
ACT Policing said officers were called to the Commonwealth Avenue hotel about 9am after two people allegedly threw rocks and a suspicious item at the building, causing minor property damage. Police said no one was injured.
The incident happened as Chief of Navy Vice Admiral Mark Hammond was speaking at the Australian Defence Magazine Congress.
Witnesses told that there were shouts in the room and some people briefly feared there was a shooter and the conference later started again.
Police said the suspicious item was taken by the AFP Bomb Response Team and was found not to be an explosive device.
A second disruption followed around midday when police searching the area found unattended backpacks in a conference room.
ACT Policing said people were moved out while the room was searched and the bags checked before they were later found not to be suspicious and their owners were located.
Region reported that attendees, including Defence Industry Minister Pat Conroy were evacuated from the main venue area during the later security response. Delegates were later allowed back inside once checks were finished.
The annual ADM Congress attracts hundreds of delegates and includes speakers from government and defence leadership.
Police said the ACT Joint Counter Terrorism Team made up of AFP Counter Terrorism, ACT Policing and ASIO was monitoring the response as investigations continued. Anyone with information has been urged to contact Crime Stoppers.
The disturbances happened on a day when anti war groups had planned to rally outside the venue and it was not immediately clear if the incidents were linked.
