Belgium's second city Antwerp announced a nighttime curfew on Monday as the country toughened social-distancing and mask wearing rules to stem a flare-up in coronavirus cases.
In the city, a major business hub and sea port, bars and restaurants will close at 11:00 pm and citizens will be obliged to get home by 11:30 pm and to stay there until 6:00 am.
Everyone over 12 years old will have to wear a face mask in public places and crowded areas, contact and adult team sports will be banned and teleworking will be compulsory for anyone whose employment allows it.
Antwerp governor Cathy Berx said in a statement that the situation in her city was such that she had decided to supplement the measures already taken on a national level.
"Stay at home as much as possible," she said, urging outsiders not to make non-essential visits to Antwerp and young people to stay indoors. "Do not go out to party, do not endanger yourself and others."
Earlier, Prime Minister Sophie Wilmes ordered that, from Wednesday, Belgians would be allowed to see a maximum of five people outside of their families, reducing their "social bubble" from 15.
Working from home will be "strongly recommended".
Wilmes's declaration came as fears grew in some European countries of a damaging second wave of the pandemic, with Britain reimposing quarantine requirements on holidaymakers returning from Spain.
Belgian health officials said there had been a rapid rise in coronavirus cases, with 1,952 new infections over the past week, up more than 70 percent on the previous week.
"The epidemiological data are worrying and we are very worried, that's why we are acting today," Wilmes told reporters, after a meeting of the country's national security council.
In addition, face masks are to become compulsory whenever people are unable to maintain a social distance of 1.5 meters, and the government is "strongly recommending" that people work from home.
Belgium had begun to ease anti-virus measures, but Wilmes said the new rules were needed "to avoid a new complete lockdown and to avoid putting the return of schools in September in jeopardy".
Frederique Jacobs, professor of infectious diseases and a spokeswoman for Belgium's federal COVID-19 taskforce, told reporters: "The rapid growth in the number of cases is worrying."
She said the situation was particularly serious in the province of Antwerp, in northern Belgium, which recorded 47 percent of new infections in the last week.
Special local measures have been taken to try to contain the spike.
But Jacobs warned that "the number of infections is also rising considerably in the rest of the country".
An average of 279 people a day contracted COVID-19 in the last week, compared with 163 a day the week before.
"Most infections are still coming among the active population, that is to say people aged between 20 and 59," Jacobs said.
Since the start of the pandemic Belgium has recorded 66,026 cases and 9,821 deaths, according to the latest data published on Monday, among the highest per capita rates of infection of any country.
A three-year-old girl with severe pre-existing health problems became Belgium's youngest known coronavirus victim last week.
Tougher rules on wearing masks came into force on Saturday with face coverings made obligatory in markets, hotels and busy shopping streets.