MONTREAL -- Wearing a mask while taking public transit will be mandatory as of July 13 in Quebec, Premier Francois Legault announced on Tuesday.

“We went progressively with this, but of course, the more we’ve opened businesses and stores, the more people there are on public transportation," Legault said. "Now I think that we are at a new stage." 

Legault made the announcement at a press conference in Montreal Tuesday morning, along with Horacio Arruda, Quebec's national director of public health, Montreal public health director Mylene Drouin and Chantal Rouleau, the junior transport minister and minister responsible for the Montreal region.

The Quebec employers council (CPQ) said in a news release that it believes the measure is "necessary to reduce the spread of the virus."

Until now, the wearing of masks has been strongly recommended by public transport authorities in Quebec, but not mandatory.

The new rule applies to everyone across the province aged 12 and up. Children between two and 12 years old are not required to wear masks, but are still strongly recommended to do so. Children under two years of age don't have to wear them, Legault added.

“There won’t be police officers, but we will be asking people who manage public transportation not let people without a mask go in," Legault said, adding that there will be a two-week grace period from July 13 to July 27 before transit agencies begin turning people away.

Fines will not be issued to users who try to enter without masks. 

"The only consequence will be that you cannot use the transport," Legault said. 

Legault added that he's counting on the population to show respect and solidarity to one another.  

“I’ve said it often, and it has been shown, since the beginning of the crisis, Quebecers have been extraordinary,” Legault said. “It is here, in Quebec, that people were the most careful; it is here that they most respected the guidelines when we look at the 60 states and provinces in North America, it is here that people followed the guidelines the best.” 

But following a spike in cases in several American states, Legault said he wants to make sure Quebec doesn't have to confine again. 

“The last thing we want in Quebec is to have to come back to where we were a few months ago,” he said. 

For the time being, the wearing of a mask isn't mandatory in other public spaces like businesses, Legault said, but he isn't ruling out the possibility. 

“It’s a question of respect, a mask is a lot more to protect others than to protect ourselves," Legault said. "Let's be smarter than the virus." 

Politicians and other advocates have been calling on the government to make masks mandatory aboard public transit for several weeks now. 

The City of Toronto announced earlier this month that riders of its public transit must wear a face mask as of Thursday. And earlier this month, Cote St-Luc, a Montreal suburb, became the first municipality in Canada to make the wearing of masks mandatory in all businesses or city-run buildings.

Arruda said on Monday the move would ensure people are ready in the event of a second wave of COVID-19 in a few months.

While he originally said he would rather people wore masks voluntarily when physical distancing isn't possible, Arruda added the province would act "if people need us to make that mandatory to get into the habit, preparing for next fall."

The public health director told a briefing in Quebec City that he senses Quebecers are letting down their guard, and he cautioned that success will depend largely on citizens following rules.

"The virus hasn't disappeared. We all have the responsibility to be prepared," Arruda said.

"We know better how the virus spreads. When it first arrived, we knew little about it, and, like the rest of the world, we learned as it progressed."

And while the COVID-19 situation is improving in the province, Arruda said the worst thing that could happen would be for Quebecers to relax on physical distancing, handwashing and wearing masks when two-metre distancing isn't possible.

Modelling released Monday by Quebec's public health institute and Universite Laval experts suggests that across the province, the probability of a second wave of the epidemic remains low during the summer, but localized outbreaks are possible in places like long-term care homes, hospitals, factories and slaughterhouses.

Projections suggest that if people continue to follow the rules, "predictions show a stabilization or a decrease in hospitalizations and deaths." But if people stop following the rules, there could be an increase in cases in July and an acceleration in August.

Arruda said he was confident the measures taken to date by the province were the right ones.

"I'm persuaded we saved many lives," he said. "We saw the deaths, we saw the cases of hospitalization, but we didn't see the cases we managed to avoid."

- The Canadian Press contributed to this report