Toronto, Ontario (CNN) -- Police fired tear gas outside a prisoner processing center Sunday in Toronto where groups of people gathered to protest the arrest of G-20 demonstrators, a security spokeswoman said.
A total of 604 people have been arrested since the protests broke out June 18, said Constable Tim Garland of the Ontario Provincial Police. At least 253 of those arrests came on Sunday, he said.
Canadian Prime Minister Stephen Harper had harsh words for demonstrators who set at least four police cars ablaze and shattered several windows around the city during the weekend's protests.
"We obviously deplore the actions of a few thugs," Harper said at the conclusion of the G-20 summit.
Some of the detained protesters were released Sunday from the prisoner processing center -- an old film studio converted to a makeshift jail amid the protests -- while others were being held for bail, Ontario Provincial Police Constable Rodney Petroski said.
Some of those released emerged in their stocking feet, carrying a bag of their belongings and speaking about the conditions inside the center.
Several detainees who had been arrested for "breach of peace" told CNN that they weren't given access to legal counsel and were denied blankets and frequent trips to the bathroom outside what they described as 6-foot by 9-foot makeshift cells.
Elsewhere, mobs scuffled with police in multiple locations, according to Neda Snyder, a spokeswoman for the Integrated Security Unit. Of the Sunday arrests, 70 took place on one thoroughfare, Bancroft Avenue, she said.
There were no reports of serious injuries to either protesters or police, according to the ISU, which said the safety of summit participants was never compromised.
"I do not believe that the individuals bent on vandalism and violence in our city have finished with their intent, so we will remain vigilant," Toronto Police Chief Bill Blair said Saturday night.
Blair told reporters that packs of disruptive demonstrators infiltrated peaceful protests in order to cause chaos and distract police.
"These criminals rely on the anonymity of hiding in a larger group of the curious and the naive," he said.
At least four police cars went up in flames and smoke during hours of confrontation, authorities said.
Protesters left behind broken windows and graffiti. Blair said police used tear gas after warning a group of protesters "engaged in acts of destruction" Saturday.
Not all encounters between police and protesters were hostile.
At one intersection the crowd danced and chanted, "You're sexy, you're cute, take off your riot suit!"
More aggressive groups of demonstrators moved from intersection to intersection, trying to circumvent police and get to the security fence protecting the summit meeting.
"The fence is a symbol that they can build a fence and spend a billion dollars on their agenda. The fence is a symbol of what's wrong with this country," protester Rolf Gerstenberger said.
Authorities said the fence was not breached Saturday.
Behind it, world leaders met for an economic summit focusing on recovery from the global financial crisis. Participants agreed on ambitious targets for getting deficits under control, pledging to cut them in half by 2013, according to a final statement made at the conclusion of the conference.
This weekend's meetings come on the heels of the two-day G8 summit outside Toronto, where the leaders of the United States, Canada, France, Germany, Britain, Italy, Japan and Russia also focused on recovery from the global economic crisis. The group also made note of other thorny issues in their final statement issued Saturday, singling out Iran and North Korea for criticism.
CNN's Jeanne Meserve, Ali Velshi, Rachel Streitfeld and Leslie Perrot contributed to this report.