MONTREAL - Anti-government protesters made good on a threat to target the Canadian Grand Prix, leading police to make 37 arrests during festivities Thursday evening.

Some of the protesters wore black and sported masks emblematic of the Black Bloc anarchist group that has caused mayhem in Montreal during a four-month student strike.

Police surrounded demonstrators who had pushed down a barricade prior to the start of the red-carpet event on the southern edge of downtown around 5:30 p.m.

Officers also made preventative arrests of protesters who were concealing projectiles in their knapsacks. The red-carpet event went off without a hitch.

Around 7 p.m. about 200 people, including some who wore masks, gathered further to the north on the main St. Catherine St. strip where Grand Prix revellers were enjoying drinks in area bars and restaurants.

A line of riot police blocked protesters from occupying the street, prompting some of the hooligans to pelt officers with rocks and other projectiles.

Police rushed the vandals, arrested dozens of them and dispersed others.

Suspects will be charged with assault, assault with a weapon and possession of incendiary devices.

Student associations and anti-capitalist associations have been threatening to stage Grand Prix disruptions since last month.

At Circuit Gilles Villeneuve on Friday morning, fans poured into the stands as usual for the popular Formula One practice event.

Local police, provincial officers and a small army of private security guards guarded Ile-Notre-Dame, clearly wary about another appearance by protesters.