Canadian police have arrested nearly 600 people in the wake of violent protests at the G20 summit in Toronto.
The latest clashes occurred on Sunday as several hundred protesters marched on a temporary detention centre for demonstrators arrested in riots the previous day during which police used tear gas against the public for the first time ever in the country's most populous city.
The weekend violence started on Saturday afternoon after groups of anarchists broke away from a larger, peaceful demonstration against the G20 summit of rich and emerging economies.
Police said protesters, many dressed in black gear, smashed windows of stores and banks and torched police cars in a protest that the authorities brought under control with tear gas and mass arrests.
Protesters said police were heavy-handed, using tactics that instigated violence rather than quelled it.
They also criticised the media for focusing coverage on violent clashes rather than the broader peaceful marches.
After a day when police admitted losing control of a violent and fast-moving crowd, the arrests came fast on Sunday.
Among those detained, for charges ranging from mischief to assaulting police, were four people who climbed through the city's sewer system and emerged near the locked-down area where world leaders were attending the summit.
About 70 people were also detained after police raided the University of Toronto's downtown campus. Police said they seized weapons, including bricks, rocks and sticks.
Anti-G20 groups started demonstrating in Toronto before the summit, which followed a smaller meeting of Group of Eight industrial nations in a resort town north of Toronto.
The security bill for the events is set to hit around $1bn.