Toronto police take away a man after one of many early-morning raids Thursday on residences in Durham and York regions, and Toronto. (CBC)

Toronto police Chief Bill Blair has shed more light on a series of pre-dawn raids Thursday morning by several police forces in the Greater Toronto Area, saying 27 people have been arrested after 30 search warrants were executed.

More arrests are expected in a guns-and-drugs investigation dubbed Project Blackhawk.

"Vast amounts of illegal drugs were seized during this investigation," along with almost 50 firearms, Blair said at a news conference.

Blair said the genesis of the operation was a tip from U.S. police in 2006 that 237 handguns had been smuggled into Canada.

Toronto Police show off handguns seized during Operation Blackhawk. (Toronto Police Service)

The resulting investigation was directly related to Thursday's seizure of guns, as well as large amounts of illegal drugs.

"Fifty-nine kilograms of methamphetamine, 400,000 ecstasy tablets, three kilos of cocaine, 60 kilograms of marijuana and a large quantity of cash," as well as illegally produced Viagra anti-impotence pills, were seized by police.

Blair said 47 firearms were also seized. In total, 82 guns were confiscated during the investigation.

The raid is linked to a previous raid on a drug laboratory in an industrial park in Mississauga on April 29.

At the time, police were tight-lipped about what they had found inside, but Blair told the news conference on Thursday afternoon that "an astounding quantity of drugs had been seized" at the Mississauga location.

"Over 4,000 kilograms of methamphetamine and ecstasy powder, including a large quantity of already processed ecstasy pills for distribution, were seized. The estimated value of the drugs seized in that raid, at that location, exceeds $160 million," said Blair.

Task force carries out sweeps

Thursday's raids were carried out by a number of police forces in the GTA, including members of the Toronto, Durham and York forces. The sweeps were co-ordinated by the guns-and-gangs task force.

Const. Wendy Drummond, a Toronto police spokeswoman, said 30 warrants were executed, half in Toronto, with the rest in the GTA and other surrounding areas.

Police searched one residence on Bellair Street in Toronto's upscale Yorkville district, where heavily armed emergency task force officers burst into a condominium building at around 5 a.m. ET and took a man away in handcuffs.

Those arrested were taken to 23 Division, in the city's north end.

Prime Minister Stephen Harper, during a visit to Huntsville, Ont., was asked about the recent killings in Toronto, as well as Thursday's raids.

He said the federal government has taken steps to reduce violent crime.

"We just recently adopted new measures, both to impose mandatory prison sentences for serious gun crimes and also to reduce bail opportunities for those who are charged with gun crimes," said Harper. "But obviously, we recognize that more needs to be done."

Toronto police said they would release more information at a news conference Friday.