Police in Toronto clashed with protesters for a second straight day as the G20 summit came to an end. In all, at least 600 people were arrested.
The greatest disruption came when hundreds of demonstrators marched on a temporary detention centre holding those detained on Saturday.
Protesters claim the police were being heavy-handed, using tactics to provoke violence rather than subdue it. For their part, officers claim to have seized weapons including bricks, rocks and sticks.
Anti-G20 groups started demonstrating in Toronto before the summit, which followed a smaller meeting of the Group of Eight industrial nations in a resort town north of Toronto.
Such international meetings have been the target of protest groups for years. Some of the worst were in 1999 outside the trade talks in Seattle.
The security bill this time is estimated to be the equivalent of just under one billion euros.