Undercover police work was a key element leading to this week's arrest of 36 people on 443 drug and gun-related charges, police said on Friday.

Police from jurisdictions across Ontario spent two years investigating the alleged guns-for-drugs operation, in which police say guns and cocaine were brought to Canada in exchange for ecstasy, methamphetamine and illicit Viagra.

Allegedly coming from labs in Ontario, the drugs reportedly made their way to the streets of major American cities.

Earlier this year, investigators working on this case, dubbed "Project Blackhawk," uncovered what they believe might be the largest ecstasy and methamphetamine manufacturing facility ever found in Ontario.

The guns brought to Canada have been traced back to a former gun shop owner in Chicago, who is also now under arrest. It is believed many of the firearms are from his personal collection.

Thursday's pre-dawn raids were conducted in the Toronto region, Waterloo, Guelph, South Simcoe and Timmins. Charges laid include 180 against one man alone, 32-year-old Sataya Vongkosy. Three others bearing that surname also face charges.

Van Nguyen, 30, faces 71 charges.

Police seized 59 kilograms of methamphetamines, 400,000 ecstasy tablets, three kilograms of cocaine and 60 kilograms of marijuana.

The ecstasy was found to have been laced with methamphetamine, increasing the chance of addiction for its users.

Police also found cash, 83 firearms -- including 48 handguns -- and 50,000 illegally manufactured Viagra pills.

Authorities say they launched the investigation in 2006 after U.S. authorities tipped them off that 237 handguns had been smuggled into Canada from the U.S.

OPP commissioner Julian Fantino praised police on Friday for the two-year probe that led to the arrests.

Ontario Provincial Police commissioner Julian Fantino said guns seized in the investigation are a reminder that Canada's gun problem is not going away.

"This investigation shows that crime guns and the associated violence are both a provincial and national issue," he told reporters at a Friday news conference. "The worst aspect of crime guns being smuggled into Ontario is that all too often those guns fall into the hands of those responsible for taking innocent lives and who terrorize our citizens."

The 38 suspects, jailed since Thursday, were expected to have court appearances throughout Friday.

With a report from CTV Toronto's Jim Junkin