MONTREAL - Police moved swiftly to shut down a protest in Montreal on Saturday, a day after a series of violent clashes between demonstrators and officers.

Between 50 and 75 people, some wearing masks and goggles, were arrested after the protest was declared illegal, police said.

Demonstrators had gathered in the rain to denounce a conference on Premier Jean Charest's plan to develop northern Quebec.

Those protesting included a group of hardline Quebec separatists, along with students, environmentalists and First Nations groups.

"I think people are starting to get frustrated," said Myriam Moore, a 21-year-old student at the Universite de Quebec, who watched the scene unfold.

"The police are abusing their power."

Only a few dozen protesters remained by mid-afternoon as the rainfall grew heavier. Many wore the red square that has become a familiar symbol of the student movement against the province's planned tuition hikes.

Riot police stood guard behind a cordoned off part of the street, where the arrested protesters were being processed and transported away.

Security was tightened around the convention centre and conference participants were asked for identification to prevent protesters from getting in.

The demonstration comes a day after hundreds of protesters clashed with police outside the convention centre as Premier Jean Charest gave a speech inside.

Friday's clashes resulted in 17 arrests and saw some of the most violent confrontations with police since protests over tuition fees began more than two months ago.

At least six people were injured, including four police officers.

Charest's highly-publicized Plan Nord promises to develop a 1.2-million-square kilometre stretch of the province's north over the next 25 years through new mining and energy production projects.

He says the plan will create 500,000 jobs, but opponents say that's unrealistic and argue it's a sellout of Quebec's resources.