MONTREAL - Highly organized arsonists used the cover of a spontaneous downtown celebration by Canadiens fans to lash out violently at police, authorities said Tuesday.

An outpouring of support for the Habs after their game-seven win over the Boston Bruins ended early Tuesday morning with 16 police cruisers wrecked, including five that were set aflame. While 10 buildings and one civilian vehicle were also damaged, police acknowledged the bulk of the violence was directed at them.

"Those young people were organized to commit criminal acts, mischief and set fire to Montreal police cars," said Montreal police chief Yvan Delorme.

"It was a kind of organization - someone watching, someone setting the car on fire, someone taking care of the others."

The overall level of organization may have been somewhat relative. One merchant said looters walked off with 14 displayed high-end running shoes - all of them for the left foot.

Sixteen people were arrested in all, including three minors. Fifteen of them were released after appearing in court Tuesday.

No serious injuries were reported, but the damage to 16 police cruisers could reach $500,000.

"I find it deplorable that last night's events have stained the celebrations and Montreal's reputation," said Claude Dauphin, the city councillor in charge of public safety.

The Montreal Canadiens issued a statement saying they "deeply regret the acts of vandalism and the wrongdoings" committed after the team's 5-0 win.

In a city with a history of Stanley Cup riots, Monday night's incident was especially alarming given Montreal's win only put the team in the second round of the playoffs.

The riot was still much smaller than many other playoff incidents, such as the riots that followed the Canadiens 1993 Stanley Cup victory and the 1994 defeat of the Vancouver Canucks.

Both those riots saw millions of dollars in damage with dozens of people arrested and several people hurt.

Montreal police had prepared unique response plans for each playoff round, anticipating a gradual escalation in aggressive behaviour.

"We will be revising that plan," said Pierre-Paul Pichette, the force's assistant director.

Pichette refused to speculate about the nature of the groups that may have sparked the violence, but called the targeting of police cruisers "worrying."

"Police vehicles represent civil authority," he said. "Is it a reflection of where we have ended up as a society?"

Delorme said police cars are usually parked out of harm's way, but they were left on the street this time to "show visibility and be welcoming."

Montreal has seen a spate of so-called anarchist violence recently, including the torching of six police cars in a station parking lot in March.

But security expert Martin Courcy, who consults for several Quebec police forces, was skeptical the rioters were anarchists or of any other ideological leaning.

"Anarchists have a tendency to hide, they (the rioters) were not hiding," he said.

Indeed many of the vandals could be seen videotaping their actions on cellphones or small cameras. Even police were stunned by the amount of video they received of the incident.

Courcy believes the heavily recorded riot is a relatively new phenomenon that speaks to disaffected youth.

"They targeted police cars because it's spectacular to put such images on YouTube," he said.

"I think they are searching for sensationalization. These are people who have problems feeling things."

Thousands of fans poured into the street Monday night after the Canadiens defeated the Bruins.

As the crowd started to disperse, vandals smashed windows and set police cars ablaze, destroying five of them and filling a small area downtown with smoke.

Most of the damage was cleaned up by mid-morning.

"You got two panels of six-millimetre glass," said Carl Gagnon of Glass Experts as he repaired a Reebok storefront.

"It's hard to break...You can maybe break one panel with a beer bottle but not both."

Police and city officials are now considering shutting down parts of Ste-Catherine Street, a major commercial artery, for the Habs game on Thursday.

"We'll make sure that if we have things that we have to adjust, they will be adjusted for the next game," Dauphin said.

Quebec's Opposition leader wants police to adopt a zero-tolerance approach when dealing with overly-expressive fans.

"When hooligans party in downtown Montreal, they amuse themselves by setting fire to police cruisers," said the Action democratique du Quebec's Mario Dumont. "Police officers have to be in position of authority."

Montreal police, however, promised not to interfere with any future celebrations, as long as they remain peaceful.

"I wouldn't want to suspend people's civil rights for a handful of individuals," Delorme said. "We are there to accompany the Canadiens fans."

Some facts about hockey-related revelry gone awry in Canada:

2008 riot in downtown Montreal

Injuries: None

Arrested: 16

Rioters set five police cars ablaze, damage 11 others and smash windows at 10 businesses after a first-round Canadiens victory over the Boston Bruins.

2006 Whyte Avenue riot in Edmonton

Injured: Two

Arrested: 49

After the Edmonton Oilers tied their Western Conference semi-final series at two games apiece, fans began throwing bottles and firecrackers. Crowds were so thick ambulances were unable to reach two stabbing victims.

2004 Red Mile gatherings in Calgary

Injured: 1

During the Calgary Flames run to the Stanley Cup finals, fans gathered on an inner-city avenue that was soon dubbed the Red Mile. At its height, some 40,000 descended on the strip, with several complaints about public drunkenness and indecency.

1994 Stanley Cup riot in Vancouver

Arrested: more than 50

Injured: 200

After the Vancouver Canucks lost game seven of their Stanley Cup showdown with the New York Rangers, more than 50,000 people descended on downtown. Damages were estimated at $1.1 million.

1993 Stanley Cup riot in Montreal

Arrested: 115

Injured: 168

A victory celebration for the Habs Stanley Cup win ended with rampant looting and vandalism. As many as 980 officers were needed to return order to downtown streets.

1955 Richard riots in Montreal

Arrested: 70

Injured: 37

Fans at the Montreal Forum were irate when NHL President Clarence Campbell showed up after suspending Maurice Richard for the rest of the season. A smoke bomb emptied the building, beginning seven hours of rioting.

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