Thousands of students protested in Montreal's downtown overnight and dozens were arrested after the Quebec government announced it would suspend the current semester for many college and university students until August.

Montreal police made 122 arrests after the protest was declared illegal shortly after midnight Thursday.

A few of the people who were detained will face charges of assaulting police officers or uttering threats, but most were arrested for taking part in an illegal protest.

CBC reporter Catherine Cullen said police and protesters clashed at the corner of Ste-Catherine and Mansfield streets.

About 50 people at the head of the demonstration wearing masks were throwing things at riot police, Cullen reported. Some shop windows were smashed and police made arrests.

Police charged and broke up the demonstration into smaller groups, which were pursued by officers. "It’s a cat and mouse game," reported the CBC’s Justin Hayward.

Pepper spray and flash bang grenades were used to disperse students, and Hayward reported students being beaten by police with batons.

'Time to cool down,' says premier

Premier Jean Charest had said Wednesday he would table a special law to allow boycotting students to finish their school semester, while taking a summer break to "restore calm" in the three-month-old tuition crisis.

"This is a time to cool down, take a breath, and take a look at the whole situation," Charest said.

But student leaders reacted angrily to the government's announcement.

FEUQ university association spokeswoman Martine Desjardins warned that government hopes of defusing the tuition crisis would likely backfire.

"If Jean Charest wanted to reduce tensions with this proposal, I'm really afraid that it will increase them instead.… Young people will remember."

Despite the premier's call for calm, the demonstrations are likely to continue. Students are calling for a mass march on Tuesday through Montreal.

The emergency law proposed by the government would affect as many as 11 universities and 14 CEGEPs across Quebec, where classes could be postponed until August, when a short catch-up session would resume.