Police are investigating an anonymous letter posted to a website dedicated to "revolutionary theory and action" that takes credit for breaking windows at a restaurant and a Projet Montréal office in the Montreal's Saint-Henri neighbourhood last Friday.

The online letter was signed by a group calling itself the Ungovernables and said the attacks were strikes against "a world that always favors the wealthiest over the poorest."

The group said its "attack" on Ludger restaurant on Notre-Dame Street West targeted "young professional yuppies" in the neighbourhood who can afford to eat there and "contribute to the exclusion of the poor."

Diners were still inside the restaurant when its front windows were smashed by about 10 people wearing hoods and masks around 11:30 p.m. and smoke bombs were thrown into the restaurant.

No one in the restaurant was injured.

'Gentrification' cited as reason

The letter said the Projet Montréal office across the street was attacked both "for their role in the gentrification of the neighbourhood" and "because it's the entire political world that we want to attack."   

The group also said it attacked a nearby IGA grocery store, though a Montreal police spokesman told CBC Montreal they have no record of that happening.

He confirmed that investigators are aware of the letter and are looking into it.

Saint-Henri has been the site of numerous incidents of vandalism against new businesses along Notre-Dame Street West by so-called anarchists and anti-gentrification groups in the last three years.

Projet Montréal councillor Craig Sauvé said such attacks aren't helping residents in Saint-Henri.

"I don't know what the strategy is behind this but all I know is that people in the neighbourhood don't appreciate it and people in the neighbourhood are getting frightened," he said.

"At the end of the day, it brings down quality of life."

With files from Lauren McCallum