Two police officers are among four people killed in a shooting in the small Canadian city of Fredericton, New Brunswick.
As many as 20 shots were fired in the incident, according to witnesses.
The slain officers were named as Sara Burns, 43, who was married with three children, and 45-year-old Robb Costello who had a partner and four children.
Police did not release the named of the two civilians killed, but they are known to be a man and a woman.
One person was arrested following the incident and was being treated for serious injuries, police said earlier.
A number of other people were also being treated for injuries.
New Brunswick Premier Brian Gallant tweeted his condolences to the victims and their families.
"During this difficult time, our thoughts are also with the courageous women and men on the front lines working to keep us safe," said Gallant.
Residents said they heard as many as 20 gunshots following a confrontation that prompted police to cordon off a large section of the city with emergency vehicles and order residents to remain inside their homes and businesses.
The shots appear to have been fired at around 7 am local time (10am GMT) in the area of Brookside Drive.
Residents said they were stunned by the scene, which occurred as people were heading to work or dropping children at a day care centre not far from the apartment complex where the shooting took place.
“This is the first time I’ve even heard of any serious crime or violent crime in this city,” said Travis Hrubeniuk, whose fiancee had just left their home when the sirens began.
Bill Henwood, a funeral director at York Funeral Home, whose business is located inside the cordoned off area on Brookside Drive, said people sat in their cars or were just standing near the blockade of police and fire vehicles “hanging tight and waiting for word” for news.
"It's not something that we expect in Fredericton to wake up and hear about. To see that there's actually fatalities is pretty extraordinary for this area. It doesn't normally happen."
The entire province of New Brunswick had 11 homicides in 2016.
However, the shooting comes as Canada wrestles with a string of violence, including an incident in Toronto last month where a man with a handgun opened fire in a crowded part of the city, killing two people and wounding 13 before he either shot himself or was killed by police.