TORONTO (AP) -- Black-clad demonstrators broke off from a peaceful protest and torched a police cruiser in the financial district and smashed windows in a shopping district after veering off from the planned protest route.
A group, dressed all in black, smashed the windows of a bank, a coffee shop and some stores before heading to an area where Canada's largest banks are headquarted, smashing restaurant and shop windows there.
The roving band of protesters in black balaclavas then turned north and broke shop windows for blocks with baseball bats and hammers. They also broke windows at police headquarters.
Police with shields and clubs earlier pushed back a small group of protesters who tried to head south toward the security fence around the site of the G-20 summit. Some demonstrators hurled bottles at police.
Previous summit gatherings have attracted massive protests by anti-globalization forces. But so far the Canadian protests have been smaller, and police hoped the rain would further thin the protesters' ranks.
Organizers of Saturday's demonstration were hoping to draw a crowd of 10,000, but only about half that number turned out.
The march, sponsored by labor unions and dubbed family friendly, was the largest demonstration planned during the weekend summits. Police were on the alert for possible violence by splinter groups.
"This isn't our Toronto and my response is anger," Toronto Mayor David Miller told CP24 television. "Every Torontonian should be outraged by this."
Police in riot gear and riding bikes formed a blockade, keeping protesters from the security fence a few blocks south of the march route. Police closed a stretch of Toronto's subway system along the protest route.
As of Saturday afternoon, 40 summit-related arrests had been since June 18, police said, with security being provided by an estimated 19,000 law enforcement officers drawn from all regions of Canada. The security costs are estimated at more than US$900 million.
Toronto Police Sgt. Tim Burrows said authorities are quite pleased that the protests have been tame so far compared to what they've seen at previous summits. Hundreds of protesters moved through Toronto's streets Friday, but police in riot gear blocked them from getting near the summit security zone downtown.
Burrows said police will be watching splinter groups within the protest who he said have promised violence.
"From what we've seen in previous summits we're quite happy with what our protesters are bringing to the table with the exception of a few," Burrows said before Saturday's march.
"They've protested peacefully. There have been a few people that have decided that they wanted to step out of line and test our response and they found themselves where they should be."
Ontario's provincial government quietly passed a regulation earlier this month allowing police to arrest anyone who refuses to show identification or submit to searches if they come within five meters (five yards) of the security fence.
Toronto's downtown core resembles a fortress, with a big steel and concrete fence erected along several blocks to protect the summit site.
Previous protests during global meetings have turned violent. In 1999, 50,000 protesters shut down World Trade Organization sessions in Seattle as police fired tear gas and rubber bullets. There were some 600 arrests and $3 million in property damage. At a G-20 meeting, held in London in April 2009, thousands protested, and one man died after a confrontation with police.
At the last G-20 summit in September, police fired canisters of pepper spray and smoke and rubber bullets at marchers in Pittsburgh.
Associated Press Writers Ian Harrison and Charmaine Noronha contributed to this report.
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