Stricter measures to curb the coronavirus outbreak will be introduced across Portugal from mid-September as students return to schools and many workers go back to the office, the government said on Thursday.

Cabinet Affairs Minister Mariana Vieira da Silva told a news conference the new measures would only be announced in early September but said the whole country would be put under the so-called state of contingency.

“The measures will be worked out over the next few days and presented after a meeting between experts and policy makers,” said Vieira da Silva.

At the moment the only area in Portugal under the contingency category is Greater Lisbon, where gatherings are limited 10 people, compared to 20 for the rest of the country.

The announcement came with the number of coronavirus cases in Portugal increasing, from 145 on Monday this week to nearly 400 on Thursday, with most of the infections reported in and around the capital.

“We do not yet know whether yesterday’s and today’s increase means there is a growing trend,” Vieira da Silva said. “It is too early to draw that conclusion.”

The southern European nation, which has reported 56,673 cases so far, initially won praise for its quick response to the pandemic, but a wave of localised outbreaks in Lisbon worried authorities and forced them to re-impose some restrictions.

Concerns are now surfacing as the around 2 million students in Portugal, a nation of just over 10 million people, prepare to return to in-person classes from September 14.

In July, Education Minister Tiago Brandao Rodrigues said face masks would be compulsory for teachers and students, who have been learning from home since March, and social distancing measures would be adopted inside classrooms.