Germany has recorded its biggest daily increase in coronavirus cases in more than three months, as countries across the region struggle to contain a surge in infections.
The latest official figures showed a rise of more than 1,200 cases in Germany in the past 24 hours.
Health Minister Jens Spahn said the increase was due, in part, to people returning from holidays.
It came as Germany warned against non-essential trips to parts of Spain.
The foreign ministry said it had added a partial travel warning to the Spanish capital Madrid and the Basque region on Tuesday amid rising infections there. Warnings were already in place for the regions of Aragon, Catalonia and Navarra.
Germany has recorded more than 9,000 coronavirus-related deaths since the pandemic began.
A 'critical moment' for Spain
Spain is facing the worst coronavirus infection rate in Western Europe. It recorded 1,418 new infections in its latest daily count on Tuesday and said there were 675 "active outbreaks" in the country.
Salvador Macip, an expert in health sciences at Catalonia's Open University, told AFP news agency the country was at a "critical moment".
"We are right at a point where things can get better or worse. This means we have to pull out all the stops to curb outbreaks before they become more serious," he said.
In total, Spain has recorded more than 326,000 cases – the highest number in Western Europe and the 11th highest in the world.
Mask-wearing compulsory in Brussels
Wearing a face mask became compulsory in all public areas in Brussels on Wednesday amid a rise in cases.
The order applies to those aged 12 and above. People were previously only required to wear masks in crowded public spaces and enclosed areas of the Belgian capital, such as shopping centres.
Authorities said the enhanced rules were introduced because of a rise in infections, with Brussels recording an average of 50 new cases per 100,000 inhabitants per day over the past week.
Police checks are being ramped up to ensure that people follow the new rules.
The mask-wearing regulation is one of the strictest currently in place in Europe.
Belgium has recorded more than 75,000 cases of coronavirus and more than 9,800 deaths, according to data collated by Johns Hopkins University.