A months-long investigation into human trafficking has led to the rescue of 18 women who were forced to work in the sex trade against their will, police said Tuesday.

Nine people are facing 33 charges, including forcible confinement, making and distributing child pornography, assault, trafficking in persons, withholding or destroying documents, living off the avails, uttering threats, obstructing police and failing to comply with court orders and conditions of bail and probation.

Ontario Provincial Police Sgt. Peter Leone said vulnerable groups, like newcomers to Canada, are often the targets of exploitation.

"These (18 victims) are individuals who were preyed upon, that were very vulnerable and certainly exploited," he said. "A lot of promises can be made to people if they come along, and they don't realize until they go with them, what they've gotten themselves unfortunately into."

Twenty-six police forces were involved in the operation on Oct. 1 and 2, including those in Edmonton, Calgary, Regina, Saskatoon, Winnipeg, Halifax, Quebec City, Toronto and other parts of Ontario.

They interviewed hundreds of women some as young as 15 since January, focusing on hotels, motels and massage parlours along major thoroughfares in 30 cities and towns across the country, police said. Many of the women had been threatened with violence, extortion and drug dependency, among other forms of coercion by men.

Halifax Regional Police say a total of 22 women in Halifax, between the ages of 15 and 25 were interviewed by the Integrated Vice Unit at local hotels.

"Investigators believe several of these women were under some level of control. The women were offered support services, including health care, outreach programs and mental health support," said Const. Pierre Bourdages in a news release.

'Violence,' 'drug dependency' part of problem

Ontario Provincial Police and the Winnipeg police said in a news release that a 12-year-old Winnipeg girl was among the people rescued during Operation Northern Spotlight II, but Winnipeg police later said that the girl was not part of the group.

The girl was interviewed by police in a separate investigation unrelated to the human-trafficking probe, said Sgt. Cam Mackid of the Winnipeg Police's Counter Exploitation Unit.

According to Ontario's Durham Regional Police Service, some of the women were being forced to perform sexual acts multiple times a day for paying male customers.

It said it interviewed 31 sex trade workers, with an average age of 26, and investigators believe nine were under some level of control.

"Although the Criminal Code section refers to this activity as 'Human Trafficking,' the public may better understand this issue as 'sex slavery,"' the police force said in a release.

"Although many of the women appear to be making their own decisions to participate for financial gain, investigators found several teenagers and young women were being forced to perform through threats of violence, physical intimidation, drug dependency and other forms of coercion."

Part or all of the money from those sexual acts were kept by their adult male controller or pimp, it said.

Leon said police provided the women they interviewed with information about support agencies in their area that could assist them, Leon said.

"Hopefully we've made a difference in their lives and given them a fresh start as well," he said.

Investigators ask that anyone who is in a similar situation, or know of someone involved, to come forward.

"We take these cases seriously and will conduct a thorough investigation, as well as protect the victims of these crimes," said Bourdages.