(AP) TORONTO — Black-clad demonstrators broke off from a crowd of peaceful protesters at the World Summit, torching police cruisers and smashing windows with baseball bats and hammers.
Police with shields and clubs earlier pushed back another small group of demonstrators who tried to head south toward the security fence surrounding the perimeter of the Group of Twenty global economic summit site. Some demonstrators hurled bottles at police.
"This isn't our Toronto and my response is anger," Toronto Mayor David Miller told CP24 television. "Every Torontonian should be outraged by this."
The roving band of protesters in black balaclavas shattered shop windows for blocks, including at police headquarters, then shed some of their black clothes, revealing other garments, and continued to rampage through downtown Toronto.
Protesters torched at least two police cruisers in different parts of the city.
Police in riot gear and riding bikes formed a blockade, keeping protesters from approaching the security fence a few blocks south of the march route. Police closed a stretch of Toronto's subway system along the protest route and the largest shopping mall downtown closed after the protest took a turn for the worse.
A stream of police cars headed to Toronto to reinforce security there after the smaller Group of Eight summit ended in Huntsville, Ontario. The vandalism occurred just blocks from where President Barack Obama and other world leaders were meeting and staying.
"These images are truly shocking to Canadians," Canadian Public Safety Minister Vic Toews said in a statement. "We are taking all measures necessary to ensure Canadians, delegates, media and international visitors remain safe."
Previous major world summits also have attracted massive, raucous and sometimes destructive protests by anti-globalization forces.
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.
Saturday's protest march, sponsored by labor unions and dubbed family friendly, was the largest demonstration planned during the weekend summits. Its organizers had hoped to draw a crowd of 10,000, but only about half that number turned out on what was a rainy day.
Toronto Police Sgt. Tim Burrows said before Saturday's protest that authorities were pleased by the demonstrators' orderly behavior. Hundreds of protesters moved through Toronto's streets Friday, but police in riot gear intercepted them, preventing them from getting near the summit security zone downtown.
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 a security fence.
Toronto's downtown resembles a fortress, with a big steel and concrete fence protecting the summit site.
Previous global summit protests 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. One man died after clashes with police at a G-20 meeting held in London in April 2009.
At the September G-20 summit in Pittsburgh, police fired canisters of pepper spray and smoke and rubber bullets at marchers.
Associated Press Writers Ian Harrison and Charmaine Noronha contributed to this report.