Four people, including two police officers, were killed in a shooting in eastern Canada on Friday in the latest in a string of gun violence across the country that has led to calls for weapons bans in cities.
Police said a suspect was taken into custody after what was the second mass shooting in Canada in three weeks.
Police in Fredericton, a city of about 56,000 that is the capital of the province of New Brunswick, said in a post on Twitter that the incident was under investigation and there were multiple fatalities.
Another police tweet said two of the four people killed were police officers but gave no details and did not release the names of the victims.
Local media images showed emergency vehicles converging on a tree-lined residential street. Nearby facilities were closed and authorities imposed a lockdown for residents before issuing an all-clear message.
"It was scary," said Marlene Weaver, who was in bed on Friday morning when she heard shots ring out in her neighborhood. "It takes you back to the shooting in Moncton."
Three RCMP officers were killed and two more were wounded in 2014 in Moncton, New Brunswick, about 195 km (121 miles) from Fredericton, in one of the worst incidents of its kind in Canada.
Canadian Public Safety Minister Ralph Goodale said the Royal Canadian Mounted Police (RCMP) were assisting Fredericton authorities in the investigation.
New Brunswick had only three homicide shootings in 2016, according to Statistics Canada.
Gun laws in Canada are more strict than in the United States but a proliferation of weapons has led to an increase in gun crimes in recent years.
"Awful news coming out of Fredericton," Canadian Prime Minister Justin Trudeau said on Twitter. "My heart goes out to everyone affected by this morning's shooting. We're following the situation closely."
On July 22, a gunman walked down a busy Toronto street, killing two people and wounding 13 others before turning his weapon on himself.
Toronto, Canada's largest city, has had 241 shooting incidents this year, resulting in 30 deaths, a 30 percent increase in fatalities.
On Thursday, Ontario pledged more money for police and to keep suspects behind bars while they await trial on gun crimes charges, as the Canadian province grapples with rising shootings involving domestically obtained weapons.