Montreal's Jacques Cartier Bridge has reopened after police in riot gear moved in to disperse thousands of student protesters who had shut down the structure for about 20 minutes Thursday afternoon at the peak of rush hour.

Police used pepper spray to push back students after warning them to leave the bridge, a major artery heading to Montreal's South Shore.

Police later rounded up protesters in Berri Square, though arrests could not be confirmed.

The students initially gathered in downtown Montreal for a march against the Quebec government's proposed hikes to tuition fees.

Student groups said the march would be peaceful as it made its way from Phillips Square to the expected destination near the intersection of Sainte-Catherine and Saint-Denis streets.

Police, including officers on horseback, monitored the demonstration as it got underway just after 1 p.m.

There were some confrontations as riot police pushed protesters away from the bridge, but there was no confirmation of arrests.

The protest was expected to be the largest demonstration yet, as more than 40,000 post-secondary students from across the province have joined an unlimited general strike.

A student protester reacts after being pepper-sprayed by Montreal riot police. (Peter Akman/CBC)

But not all students support the action. Some who have spoken out against the strike say they have received threats.

Arielle Grenier, a student at the University of Quebec in Montreal, said she was booed and shouted down when she tried to explain her position opposing the strike.

Another student posted a message on Facebook encouraging students to flood her page with pro-strike messages.

"I received a post that said they wanted my head on their desk," she said.

She said she supports tuition increases and wants the right to express her views and continue attending her classes.

Latest in series of protests

Thursday's protest is the latest in a series of escalating demonstrations by students opposed to increases that will see tuition rise by $1,625 over the next five years.

Last Friday, Montreal police arrested 37 people, including eight minors, after they allegedly broke into and vandalized the CÉGEP Vieux-Montréal on Ontario Street.

In November, more than 20,000 students marched on Premier Jean Charest's Montreal office in a similar demonstration against the rising fees.

Alex Magder, a student at Dawson College, said the debate has been heated at his school.

"There are people who are very passionate on both sides who are maybe a bit caught up in the issue and don’t really think clearly when it comes down to it," he said.

Students at Dawson will vote next week on whether they’ll join the strike.

Non-confidence motion

A non-confidence motion on proposed tuition fee hikes will be debated in the National Assembly on Tuesday.

The province says that even after the increases, Quebec university students will still be paying less than the Canadian average for a higher education.

Average undergraduate tuition fees for full time students in 2011-2012

Quebec 2,519 Newfoundland and Labrador 2,649 Manitoba 3,645 British Columbia 4,852 Prince Edward Island 5,258 Saskatchewan 5,601 Alberta 5,662 Nova Scotia 5,731 New Brunswick 5,853 Ontario 6,640

Source: Statistics Canada