Police Superintendent Despa Fitzgerald said the operation began shortly after 10:20am, when emergency services responded to a van on fire at a Dulwich Hill apartment block. Residents told responding officers they saw the man in the van, which had been stolen from the nearby area a couple of days earlier. He threatened them with a shotgun as he fled the apartment block and set the vehicle ablaze. No shots were fired.
The police response included a three-hour exclusion zone across several streets around Williams Parade, and local public schools were placed in lock out. The search involved riot squad officers, officers in bulletproof vests, police dogs and the PolAir helicopter.
The man was reported to be wearing a blue T-shirt and long black pants, and fled down Union Street towards Laxton Reserve. Police later released an image as part of their investigation of a man with a dark jumper, black cap and white shoes. His identity has not been confirmed.
Police have described the man as Caucasian, about 20 years old, about 160 centimetres tall and of a slim build with shaggy brown hair.
Superintendent Fitzgerald said sightings of the man should be reported to Triple Zero (000), and asked anyone with mobile phone or dashcam footage to share it with investigators.