"Unprecedented and Unspeakable loss."

CTV.ca News Staff

Four police officers were shot and killed after conducting a raid on a marijuana grow operation northwest of Edmonton on Thursday.

It's the worst single loss of life for police in Canada in 120 years.

"It is with profound sadness that I confirm that four members of the Royal Canadian Mounted Police were killed today in service to our country," said RCMP Commissioner Giuliano Zaccardelli at an 8 p.m. ET news conference in Ottawa.

"It is an unprecedented and unspeakable loss."

At approximately 10 a.m. MT, a shootout broke out between police and a male suspect at a farmhouse in Rochfort Bridge near the community of Mayerthorpe, about 130 kilometres northwest of Edmonton.

RCMP spokesman Cpl. Wayne Oakes said the four officers were at a Quonset shed on the farm when they were shot by the suspect, whose body was also found in the shed.

He added that the suspect was known to police, but would not say if the man had a criminal record.

The Canadian Press reports that, according to a government source, the suspect killed himself after shooting the officers.

Oakes said emergency responders went into the shed and found the dead officers.

At a news conference in Mayerthorpe, RCMP Assistant Commissioner Bill Sweeney said: "As you can well imagine, the loss of four police officers is unprecedented in recent history in Canada. . . . It's devastating."

Most Sacred Heart of Jesus, have mercy on them.