Several French cities on Thursday announced new face mask requirements and other measures to contain the coronavirus as the number of new cases continues to increase after a long lull, officials said.

The government, anxious to avoid a new outbreak but wary of clamping down too hard during the summer holidays, has stepped up guidance on social distancing as officials report new contagion “clusters” daily.

Face masks are already required in all enclosed public spaces nationwide, and in recent days several cities have cracked down on mass gatherings of young people in particular.

In the Nord department adjacent to Belgium, the government’s top official said “reinforced measures” would be announced Friday, possibly making masks compulsory in public even outdoors, in response to a surge in cases across the border.

The mayor of Saint-Malo, whose walled city on the English Channel has drawn tens of thousands of French tourists who opted to stay in the country for the summer holidays, said masks were now mandatory inside the old city and on the ramparts for everyone aged 11 and above.

“Masks are essential protection for limiting the virus’s spread,” Mayor Gilles Lurton said, after health authorities said the Ille-et-Vilaine region had 44 new cases on Wednesday alone.

Starting Friday, masks will be required in open-air markets in Orleans, central France, and after 9:00 pm (1900 GMT) along the Loire river, where crowds of people have been turning out nightly.

France’s health ministry reported Wednesday 15 new COVID-19 deaths in the past 24 hours, bringing the overall toll to 30,238 since the outbreak began.

While far below levels seen at the peak of the crisis, the number of new daily cases has been above 1,000 for several days, and the “R” rate of viral transmission has risen to 1.3 nationwide -- meaning 10 infected people are infecting 13 others on average.

Health Minister Olivier Veran, visiting a mask distribution operation in a Paris suburb Wednesday, urged people to wear masks “if you’re in the street full of people, and not sure about being able to keep a safe distance.”

Digital Affairs Minister Cedric O, meanwhile, told CNews television on Thursday that only 2.0 million to 2.5 million people had downloaded the government’s StopCovid contact tracing app, which uses cellphones to alert people if they cross paths with COVID-19 carriers.

Critics say the app has been a flop since its long-delayed launch in June, as tens of millions of people would need to activate the system to be useful for containing a second wave of cases that could again overwhelm hospitals.

“I admit it’s a little difficult to give results now, it’s still too early,” O said. “But I think that if the epidemic resurges, we won’t be unhappy to have this in our toolbox.”