MONTREAL -- A COVID-19 outbreak linked to two house parties south of Montreal has grown to about 80 cases, Quebec's public health director announced Friday.

Horacio Arruda said there was "sufficient data" to conclude the outbreak is linked to two private parties that took place at the end of June, as well as to a bar that some of the attendees later visited.

"That means there was community transmission at the parties, then there was more at the bar by people who were contaminated in the parties who didn't have symptoms, or who had mild symptoms," he told reporters in Gatineau, Que.

The outbreak prompted one of the affected communities to order mandatory mask-wearing inside all commercial businesses as of Friday.

Health officials said they believe the house party in the municipality of Saint-Chrysostome, located about 50 kilometres south of Montreal, is connected to a series of infections that forced several businesses to close in the nearby town of Mercier.

Montreal has already announced it intends to bring in a bylaw making mask-wearing mandatory in public indoor places by the end of July.

Arruda said provincial officials continue to seriously discuss whether to implement similar rules across the province, but said it's easier said than done. "Making things mandatory is easy to say, applying it, now, there are a lot of logistics," he said.

He said it will take time for cities to figure out how to provide masks to those who can't afford them, how to enforce the rules, and what penalties to impose on people who break the rules.

The province tightened restrictions on bar owners earlier this week out of concern some weren't following physical distancing rules.

As of Friday, bars and nightclubs can no longer sell alcohol after midnight and are limited to 50 per cent of their legal customer capacity -- something Arruda said is necessary to limit crowding and reduced inhibitions brought on by alcohol.

He said it's up to bar owners and patrons to respect the rules and avoid new closures. "We're trying to keep a sector of the economy open because people want to have a drink with others, but they can't have a drink like before," he said.

Premier Francois Legault was asked on Friday whether the recent uptick in cases were indicative of a second wave of COVID-19 infection.

Although he said he didn't believe public health officials think so, he said, "there is a risk."

"The last thing we want is to reconfine so wear a mask, especially in closed public places, and keep a two-metre distance between people, it's very, very important -- more than ever."

This report by The Canadian Press was first published July 10, 2020.