HALIFAX -- Police in Atlantic Canada's largest city are warning drug users their lives are at risk because of the emerging presence of illicit fentanyl on the streets.

Halifax police say while the city isn't in the grip of the deadly opioid crisis faced by other parts of Canada, officers have found illicit fentanyl six times during drug raids since Jan. 1.

"We want to get the word out to recreational users buying pills on the street," Staff-Sgt. Darryl Gaudet said in an interview Wednesday.

"You are playing Russian roulette in relation to buying pills from a drug dealer."

Investigators seized fake oxycodone pills made of fentanyl powder from six homes.

Gaudet said while it's still early in relation to the appearance of the potent drug, police are trying to stay on top of developments by warning those most likely to use it.

Last fall, Nova Scotia's chief public health officer said the province needed to prepare to deal with a potential wave of deaths due to illicit fentanyl in a whole range of street drugs. He released figures showing that fentanyl was connected to as many as 10 deaths in the first nine months of 2016.

Gaudet said the recent drug raids turned up quantities of pills numbering from hundreds to thousands, but he said there was no evidence the drugs were being manufactured locally.

"We've had no pill press operations here yet," he said. "We are in the process of trying to determine if we have any."

Gaudet said police were following up on some leads into where the pills originated.

Police said the pills are typically dark green or light blue, and they are manufactured to look authentic by stamping "CDN" on one side of the pill and "80" on the other.

They also said fentanyl can be used to cut cocaine or to make fake crack cocaine, although there have been no lab tests that have confirmed fentanyl in any cocaine seized so far.

The Halifax police warning followed one issued Tuesday by RCMP in southern Newfoundland about cocaine containing fentanyl being sold in communities along the Burin Peninsula.

Police say fentanyl can be up to 100 times more potent than morphine and 20 times more toxic than heroin. British Columbia declared a public health emergency in the wake of hundreds of deaths there.

Gaudet said just two milligrams of pure fentanyl is enough to kill the average adult.

"It doesn't take much, it's like two grains of salt that could kill you," he said.