Over 150 protestors were arrested when thousands of anti-G20 marchers resorted to "wanton criminality" here, setting ablaze police vans and smashing windows with baseball bats, prompting authorities to lock down the summit venue into an intense security zone.
Police used shields, clubs, tear gas and pepper spray to push back a group of black-clad protesters who tried to head south toward the security fence surrounding the perimeter of the Group of 20 summit site where world leaders, including Prime Minister Manmohan Singh, are expected to meet.
"We have never seen that level of wanton criminality and vandalism and destruction on our streets," Toronto Police Chief Bill Blair said at press conference on Saturday.
"I am profoundly disappointed in the criminal acts which have taken place," he said.
"I have seen windows broken and police cars burned. It is very regrettable that such vandalism and violence could not be prevented ... I want to assure you that the persons responsible will be held accountable," he added.
Blair blamed the destruction on violent "anarchists" and said several of their leaders were arrested.
Blair confirmed that tear gas was deployed once - for the first time in the city's history - "after a warning was given to the public about its impending use."
He denied the use of rubber bullets.
The size of the protest crowd was estimated as high as 10,000.
As the evening wore on, the area around the Ontario legislature at Queen's Park emerged as a major focal point. Several hundred police in riot gear - many on horseback -ringed government buildings and lined streets in the area, as well as the nearby park grounds.
Miller said police made thorough preparations ahead of the summit and did a "commendable job under difficult circumstances."
"I'm sure there have been small moments where perhaps there are some tensions between a crowd and the police ... In the broad brush, I think we should be very confident in their work," Miller told reporters.
Canada spent over USD 1 billion to secure the G8 and G20 summits, hoping to avoid the violent protests that marred recent gatherings of these global forums in Pittsburgh and London.