Fredericton Police confirmed on Twitter that "at least four people killed" in the incident. The cause of shooting in the capital of New Brunswick province was not immediately known.
"The police were here earlier and wanted me to leave, but I said I couldn't leave my dog behind The police officer told me to stay away from the windows and to lock the doors".
New Brunswick had three homicide shootings in the entire year of 2016, according to Statistics Canada.
He said he heard similar sounds about five minutes later.
Fredericton is the capital of New Brunswick, a province on the eastern side of the country and above ME in the USA.
David MacCoubrey told the Canadian Press that it was shortly after 7 a.m. when he awoke to the sound of gunshots that sounded like they were "10 metres" from his bed in his apartment on Brookside Drive.
Prime Minister Justin Trudeau on Twitter said his "Heart goes out to everyone affected by this morning's shooting". "Obviously, we have no way of knowing at this time what the situation is, but there seems to be the same level of worry and fear".
The shooting incident began at about 7 a.m.at an apartment complex on Brookside Drive.
A 28-hour manhunt ensued before police caught up to the suspect and arrested him, in what was described as the second-deadliest attack on the Royal Canadian Mounted Police (RCMP) since four officers were ambushed on a Mayerthrope, Alberta farm in 2005.
Residents said they heard as many as 20 gunshots following a confrontation that prompted police to initially cordon off a large section of the city with emergency vehicles and order residents to remain inside their homes and businesses.
"It's been a very hard day for our officers and the residents of our fine city as we come to terms with the violent death of four of our people in our city, two of which, as you know are officers", said Police Chief Leanne Fitch. "It's a really challenging field and to survive you need to keep all of those in check", she said when she first applied to police academy. The local police have also tweeted asking the local population to avoid calling the police station directly due to a high volume of calls.