Administrators at the University of Quebec in Montreal (UQÀM) are suspending classes in the undergraduate law program, after an attempt to resume classes Wednesday morning ended in chaos.

Hundreds of protesters, many of them masked, stormed the downtown university's buildings around 9:30 a.m. ET, just as undergraduate law students with a court injunction were set to resume their courses.

The mayhem ended with classes being cancelled for the day.

Administrators later decided to suspend classes in the BA law program until Friday, inclusively, "out of prevention and security" concerns, said UQÀM media relations director Jenny Desrochers.

The suspension affects about 50 scheduled lectures and 600 students.

Classroom confrontations

Carrying a list of scheduled classes, protesters marched through UQÀM pavilions blowing whistles and banging on drums as they searched for students gathered in lecture halls.

A masked protester would yell out marching orders for the next target, such as: "Pavilion M!"

At one point, protesters climbed nine flights of stairs before entering a contract law class, where they flicked the lights on and off and yelled "scab!" as a small group of students sat, stunned.

A few men grabbed two female students by the arm, telling them to get out.

One spray-painted a red message on the wall of the classroom: "On strike, dammit!"

Students said afterwards that once the protesters moved on, their professors fled and classes abruptly ended.

Law student Christina Macedo was heckled as she tried to explain to journalists what happened in her classroom.

"This morning they came in and ruined everything. They told us 'get out,'" she told reporters, as protesters tried to shout her down. "They were trying to break our phones. Then we left."

One masked demonstrator, who identified himself only as Éric B., insisted the protest was peaceful.

"Me myself, I would have never acted on violence," he said.

A protester holds up a sign. (CBC)

"I would have never gone upstairs if people were there to break stuff. We have to stop just always demonizing people, always saying the reds are terrorists and shit like that. That's totally BS."

Students opposing the tuition hike, known as the "reds," have been sporting a red square symbol since the student strike started 14 weeks ago.

The students who support the tuition increase and want to return to class are known as the "greens" for the green squares they've adopted.

Éric B. argued it was the greens who were violent during the incident at UQÀM Wednesday morning.

Macedo said she saw the incident differently.

"Peaceful? I really don't see it was peaceful at all," she told CBC News as she was jeered and shouted down by a group of demonstrators outside the school.

"I'm trying to respect our right [to] go back to school!"

Injunctions granted to some academic programs

UQÀM went to court last week to get an injunction to allow students who want to return to class resume their studies.

The undergraduate law students' association has voted to return to class. But students in the program are also members of a separate faculty association that includes political science majors — that group has voted to continue the tuition boycott.

Undergraduate law students are in a bind because of their competition affiliations, explained Desrochers. School administrators are meeting with executive members of both student groups to determine how to proceed.

Scenes like the one at UQÀM Wednesday morning have been playing out for the past few weeks at CEGEPs (Quebec's college system) across the province, where students have court injunctions to return to class.

In many cases protesters blocked school entrances, preventing students and administrators from entering buildings.