Germany could see up to 10,000 new coronavirus cases each day if social distancing and hygeine measures aren't followed, the country's disease control agency warned, as it recorded its highest daily infection total since April.
There were more than 4,000 cases in a a 24-hour period confirmed on Thursday by the Robert Koch Institute (RKI).
The announcement raised fears the pandemic is picking up pace in a country that so far has coped better than many of its European neighbours.
Figures from the RKI showed an increase of 1,200 new infections compared to Wednesday - 4,058 cases, compared to 2,828 the previous day.
THe country logged over 6,000 at the height of the pandemic.
It came as Lothar Wieler, RKI's head, delivered a stark warning, saying that Germany could see up to 10,000 new cases each day if people do not follow social distancing and hygiene measures.
"It is possible that the virus will spread out of control," he told reporters in Berlin.
"We do not know how the situation in Germany will develop in the coming weeks. It is possible that we will see 10,000 new cases a day," he added.
Health Minister Jens Spahn has said he was “very concerned about this”, urging people to follow COVID-19 prevention measures.
Andreas Gassen, who heads Germany's National Association of Statutory Health Insurance Physicians, said the country is conducting over 1.1 million tests a week, of which only about 1.5% are positive — a far lower rate than in the spring, suggesting fewer infections are going unnoticed.
Gassen also noted that Germany still has 8,500 free intensive care beds and a further 12,000 that can be mobilized within seven days, should the number of serious cases rise suddenly.
Spahn played down the possibility of imposing a national lockdown, saying he preferred regional measures.
Authorities in Germany on Wednesday urged people not to travel to and from regions with over 50 new cases per 100,000 residents in the past week, which includes the cities of Bremen, Remscheid, Hagen, Hamm and parts of Berlin.