A night-time curfew will be imposed in several Portuguese municipalities, including the capital Lisbon and the city of Porto, as authorities scramble to bring under control a surge in COVID-19 infections, the government said on Thursday.

The 11 p.m. to 5 a.m. curfew, which starts on Friday, will be in place in 45 municipalities across the nation, which faced its toughest battle against the coronavirus in January.

Coronavirus cases jumped by 2,449 on Thursday, the biggest increase since mid-February. Daily coronavirus deaths, in single digits, remain well below February levels, however.

“We are not in any circumstances to claim that the pandemic is in control,” Cabinet Minister Mariana Vieira da Silva told a news conference. “This is a time to follow the rules, avoid gatherings, avoid parties, and seek to contain the numbers.”

Vieira da Silva said new cases were mostly being reported among unvaccinated young people. Authorities are speeding up the vaccination campaign to tackle the surge, with those aged 18 to 29 receiving their jabs from next week.

People living in Lisbon’s metropolitan area, where most new cases are concentrated, must still present a negative coronavirus test or a vaccination certificate to leave or enter the region at the weekend.

In total, Portugal, which has fully vaccinated around 31% of its population, has recorded 882,006 cases and 17,101 deaths since the pandemic began.

Authorities have blamed the Delta variant for the rise. It accounts for more than half of cases in the country, which has the European Union’s second highest seven-day rolling average of cases per capita.