Many Sydneysiders have reported having their sleep disturbed last night following a Blackhawk helicopter training exercise.
People from the lower north shore and inner west suburbs tweeted about the helicopter activity, which happened at roughly 2.30am.
PolAir, the NSW Police Force Airwing, released a statement regarding the army exercise.
"Australian Army helicopters and personnel are taking to the skies over Sydney this month (November 2017) – practising operations against simulated terrorist targets across the city
"The Black Hawks and soldiers are taking part in scheduled counter-terrorism exercises using civilian locations around the CBD and Sydney Harbour.
"The public should not be alarmed if they see low-flying helicopters, vehicles and military personnel or hear the associated noise of the helicopters, blank gunfire and pyrotechnics.
"The training uses schools, shopping centres, residential buildings and transport hubs, locations chosen for their training value and the added realism that comes from training in these areas. People who see the training should not be concerned – these locations are not under any form of actual threat.
"Training such as this helps ensure Australia has among the best counter-terrorism response capabilities in the world.
"Additional parts of this training will occur in the Parramatta, Holsworthy/Liverpool and Hunter regions.
"The ADF is unable to provide media access or further information, including specific timings, regarding this training in order to protect operational tactics, techniques and procedures. Individuals with concerns should contact: firstname.lastname@example.org."