Canadian police say a suspect is in custody after at least four people - two of them police officers - were killed in a shooting in the eastern city of Fredericton, New Brunswick.
The city police confirmed the officers' deaths on Twitter.
The pair have not been named, and the circumstances around the incident remain unclear.
Police have advised residents of Brookside Drive to "stay in their homes with doors locked at this time".
A local TV reporter said he heard four gunshots just after 07:00 (11:00 GMT).
Nick Moore, a journalist from CTV Atlantic, posted video footage of the scene on Twitter, showing emergency vehicles outside a house.
"Awful news coming out of Fredericton," Canada's Prime Minister Justin Trudeau tweeted.
"My heart goes out to everyone affected by this morning's shooting. We're following the situation closely."
Fredericton is the capital of New Brunswick province and home to around 56,000 people.
Gun laws are more stringent in Canada than in the US, but the number of shootings has nonetheless risen in recent years.