TORONTO - Toronto nursed its post-G20 migraine Monday amid concerns police had smashed civil liberties like Black Bloc vandals taking pickaxes to a Starbucks window.

Police and politicians rushed to defend what appeared to be arbitrary searches, seizures, arrests and detentions amid a chorus of condemnation from rights activists.

"We were met this weekend with a number of people — certainly several hundred — who wished to use the opportunity available to them during a peaceful democratic protest to commit violent acts," Toronto Mayor David Miller said.

Officers showed "admirable professionalism" and did an "extraordinary job in almost impossible circumstances," Miller said.

Police activity picked up markedly starting Saturday evening after afternoon riots saw tiny groups of vandals smash some windows and set police cruisers alight.

More than 700 people were rounded up over the weekend. Some were rousted from their beds. Others were simply dragged from crowds.

The Integrated Security Unit said 900 G20-related arrests were made since June 18. The ISU reported that, as of Sunday morning, eight officers and six civilians suffered minor injuries.

Among those detained were members of the media, including several who found themselves trapped for hours between police lines in the rain on Sunday at a downtown intersection.

Others complained of incarceration without access to a lawyer and threats from police.

Several hundred people, including some who had been arrested, expressed their displeasure outside police headquarters late Monday afternoon.

Canadians didn't want to pay the $1 billion security tab for the twin summits, so the police found a way to justify the cost, left-wing writer Naomi Klein told the throngs of cheering demonstrators.

"The bosses of this police force and other police forces decided to play public relations, and instead of doing their jobs, they let the city burn," she said. "They let those cop cars burn."

Some called for a public inquiry into the use of force by police, which many described as excessive and unwarranted. Others showed their displeasure with signs that branded the detention centre "Torontonamo."

Protesters weren't the only ones to see their civil liberties thrown out the window over the weekend, said John Clarke, an organizer who spearheaded an infamous demonstration at the Ontario legislature a decade ago that turned violent.

"I was at the University of Toronto and squads of eight and 10 officers were stopping everyone, illegally searching them, frisking them, confiscating things from them," Clarke said.

"People who weren't even protesters were affected by the massive, quasi-police state that was established."

Nathalie Des Rosiers, general council for the Canadian Civil Liberties Association, planned to issue a report Tuesday unequivocally condemning some of the police tactics.

"We have police brutality, illegal searches, arbitrary detentions, people being asked all sorts of questions and being harassed," Des Rosiers told The Canadian Press.

"It's unconstitutional, it's illegal and it should not happen."

Des Rosiers did say police acted professionally in many instances, but their orders clearly changed after Saturday afternoon's rampage.

Requests for comment from the Integrated Security Unit or Toronto police Chief Bill Blair were not immediately answered.

On Saturday, as police vehicles burned and militants rampaged freely, police and politicians said it was more important to protect the summit security zone.

The hours-long detention of the crowd at the intersection Sunday was justified as a response to the threat of more violence in the streets. Police said they believed members of the march were poised to engage in Black Bloc tactics.

Anarchists employing the tactic infiltrate large peaceful demonstrations wearing normal street clothing. They then change into black clothing and cover their faces in balaclavas or ski masks before fanning out and destroying symbols of capitalism.

Jesse Rosenfeld, a freelance correspondent for the British-based Guardian newspaper, who spent a night in detention after an aggressive arrest, called police behaviour "brutal, violent and repressive."

"It was a direct attempt to sweep the debate that is coming from the ground up off the streets," Rosenfeld said.

Federal New Democrats said they wanted to know who requested the "temporary suspension" of basic civil liberties "in secret."

The party's safety critic, Don Davies, said those involved in summit security had to answer to how demonstrators and journalists were treated.

"I will be asking the Public Safety Committee to get to the bottom of these lingering questions," Davies said.

Ontario's New Democrats also expressed "serious concerns" over whether fundamental rights were trampled and called for a public inquiry.

Cleaning up the mess left by the vandalism was among the other headaches for the city.

Miller said Ottawa should pay the costs.

"This is a federal responsibility," Miller said. "It's their conference."

While Ottawa has said it might compensate businesses for any G20-related revenue fall, it also said there would be no money for repairing acts of vandalism.

The mayor did not have a cost estimate of the damage.

After last week's exodus of workers avoiding the downtown core, the streets showed their typical Monday morning bustle as workers repaired the smashed windows of Queen Street bank.

The imposing concrete and steel barrier around the summit meeting site — which earned the city the moniker "Fortress Toronto" — began slowly coming down, a process expected to take several days.

One downtown worker, Christy Doney, said she was surprised the city was so clean despite the graphic scenes she witnessed on the weekend news.

"I didn't think it would get quite to that extreme, but I wasn't expecting it to be peaceful either," she said.

Hydro One employee Jiten Mistry said the images reminded him of the violent mobs he has witnessed in other countries.

"I guess this happened for the first time in Toronto," he said. "So yeah, it was shocking."

— With files from Mary Gazze, Dan Robson and Maria Babbage