MONTREAL - Montreal city council has passed a bylaw banning protesters from wearing masks during demonstrations "without a valid excuse."

The measure proposed by Mayor Gerald Tremblay's Union Montreal passed Friday in a vote of 33 to 25.

The bylaw will come into effect on Saturday, May 19. The bylaw has to be announced publicly in the morning newspapers before it takes effect.

While the bylaw has been criticized by civil liberties advocates, Tremblay said the city had to take action against the ongoing protests _ which have sometimes led to clashes vandalism and clashes with police.

"Our cities in Quebec can no longer be considered a target, we have to take back our cities," he said at a news conference Friday.

The move bis a response to the near-daily demonstrations that have cost the city millions in lost productivity, along with some smashed windows, clashes with police, and numerous injuries.

The proposed rules would give police the power to fine those wearing masks, with penalties ranging from $500 to $3,000.

Student groups and civil libertarians have denounced both moves, saying they violate the right to freedom of expression and the right to protest.

Several dozens of protesters came to City Hall on Friday to express their opposition to the bylaw.

Opposition leader Louise Harel had previously expressed support for the proposed bylaw but her party opposed it in the vote Friday.

Tremblay eventually cut off debate after opposition parties Projet Montreal and Vision Montreal vigorously opposed the proposal.