Paris, Sep 5 (IANS): Twenty-two schools and over 100 classes in France were closed due to the spread of the coronavirus, Education Minister Jean-Michel Blanquer announced, three days after the opening of schools across the country.

"In mainland France, there are now 12 (schools) closed out of a total of over 60,000, which is small figure. In La Reunion (an overseas department), there are 10 schools," Blanquer told local broadcaster Europe 1 on Friday.

"In general, (the detection of) three cases of COVID-19 infection would trigger the closure of a school," he added, noting that all the relevant cases had been infected before the return to school, Xinhua news agency reported.

Some 12.4 million students in France returned to classrooms on Tuesday. Under the government's back-to-school plan, students aged over 11 must wear face masks all the time, including in classrooms. Schools have to limit the flow of pupils and parents during the rush for arrival and departure. In addition, classrooms should be regularly disinfected and ventilated.

The start of the new academic year came amid worsening sanitary indicators. On Thursday, the second day in a row, more than 7,000 patients have caught the virus, and the cumulative number of cases reached 300,181, according to figures from the country's public health agency.

The number of hospitalised patients rose by 11 to 4,643, of whom 464 needed intensive care, up by 18. The two indicators, which are key for evaluating the ability for hospitals to cope with the epidemic, have been increasing since the end of August.