A gunman who dressed as a policeman killed at least 16 people in the Canadian province of Nova Scotia during a 12-hour rampage in what was the country’s worst modern-era mass shooting, media reports said.

The gunman, 51-year-old Gabriel Wortman, who worked as a denturist, had also disguised his car to look like a police cruiser, the Royal Canadian Mounted Police were quoted as saying in a Reuters report.

The rampage ended in a car chase, which saw the attacker dead, reported BBC.

Residents in the rural town of Portapique had been advised to lock themselves indoors after the attack began on Saturday.

The gunman shot people in several locations across Nova Scotia which meant authorities were still trying to establish the final death toll, police said on Sunday, warning that that there may be more victims.

Canadian Prime Minister Justin Trudeau described it as "a terrible situation", the BBC report said.