World Bulletin/News Desk
The incident was one of the worst of its kind in Canada, where fatal attacks on police are rare.
Police cordoned off a large area in the northwest of the city and warned residents to stay inside their homes. A large blue armored police truck entered the area early on Thursday morning and a helicopter hovered overhead.
Schools and government offices were shut in the small city of 70,000 in the east coast province of New Brunswick. Police told residents not to tweet the locations of officers for fear they could be helping the gunman.
The Royal Canadian Mounted Police have been hunting Justin Bourque, 24, after three officers were killed late on Wednesday and two more were taken to hospital with non-life threatening injuries.
The last mass killing of Canadian police took place in Mayerthorpe in the western province Of Alberta in 2005, when a gunman killed four officers before shooting himself. The losses were the most the RCMP had suffered in a day for 100 years.
Local media in Moncton published a photograph of a man in camouflage clothing and a black headband carrying a rifle. Reuters could not immediately authenticate the picture.
A Facebook page purporting to belong to the shooter was filled with posts critical of the police and those who backed gun control.
Police declined to give any details about Bourque. A spokeswoman said a news conference was scheduled for 11 am eastern (1500 GMT) on Thursday.
City officials said there had been no murders in Moncton in all of 2013 and none had been recorded this year until Wednesday.
Resident Will Njoku said at first he thought the shots had been firecrackers but then he heard sirens.
"My neighbor called and said there was a gunman on the loose and they were just down the road and it kind of freaked us out," he told the Canadian Broadcasting Corp.
"I jumped out of my house and started directing traffic away ... I knew people going down there would be in danger."
Njoku said he was in the basement of his house with his wife and three young children.
Speaking at a press conference late on Wednesday, RCMP spokesman Damien Theriault choked back tears after he was asked how police were dealing with the shootings.
"We are professionals," he said.
Canadian Prime Minister Stephen Harper said in a statement the deaths of the officers would be honored and remembered.Last Mod: 05 Haziran 2014, 15:28