Four people have been killed and another injured in the Australian city of Darwin.
The 45-year-old suspect, who was known to police, was arrested about an hour after the first shots were fired on Tuesday.
Police said the gunman carried out attacks at several locations and may have been searching for a “specific individual”.
It was not terror-related, they added.
Authorities have not identified the victims or the suspect.
Mass shootings in Australia have been a rare occurrence since the country overhauled its gun laws in 1996, in the wake of a shooting in Tasmania that left 35 people dead.