Anti-Olympic demonstrators waving anarchist flags and causing some vandalism marched through the downtown streets of Vancouver as the Winter Games action got under way on Sunday (NZT).
As many as 300 young people, many dressed in black with their faces covered, overturned mail boxes, painted vehicles and smashed windows at a department store in a protest billed as an effort to "Clog the Arteries of Capitalism."
They also scuffled with pedestrians along the route.
Police, some wearing riot gear, were out in force to meet the demonstrators and urged civilians to stay out of the way, before eventually splitting the marchers into smaller groups that were easier to control.
Seven people were arrested on charges ranging from illegal weapons to assault, and police blamed the vandalism on unnamed "criminal elements" which had "taken over infiltrated legitimate protests" against the Games.
A protest on Saturday (NZT) during the opening ceremony ended peacefully, but police said the more violent tactics used on Saturday meant they would also change tactics if it happened again.
"We don't believe the protesters or criminals should be in a position to disrupt the Games. So far they haven't," Vancouver Police chief constable Jim Chu said.
The Vancouver Games have drawn opposition from anti-poverty and anti-globalisation groups who say the event wastes money better spent on social needs and the massive security is designed to protect corporate sponsors.
Police said Saturday's event involved protesters from other parts of Canada and the United States, and several demonstrators said they had come to Vancouver because of the Games.
The protests on Saturday and Sunday attracted attention but the number of demonstrators has been dwarfed by the tourists and residents wandering the downtown area for Olympic-related events.
A long line people could be seen walking to a plaza along the downtown waterfront to see the outdoor Games cauldron which was ignited on Friday by Canadian ice hockey great Wayne Gretzky.