Germany is experiencing a "worrying jump" in coronavirus cases after the daily infection rate passed 4,000 for the first time since early April, the health minister, Jens Spahn, has said.
"The numbers are showing a worrying jump," Mr Spahn told reporters in Berlin. "Barely any other country in Europe has managed the crisis as well so far. But we must not gamble away what we've achieved."
The largest economy in Europe could also see an "uncontrolled" spread of coronavirus unless it gets things under control, according to Lothar Wieler, the head of the Robert Koch Institute.
"We don't know how the situation in Germany will develop in the coming weeks," Mr Wieler said. "It's possible that we will reach more than 10,000 cases a day. It's possible that the virus will spread uncontrollably. But I hope it doesn't."
He added: "The current situation worries me a lot... I ask you to stick to the rules," adding that only eight per cent of cases in Germany were imported from overseas.
In the past 24 hours, 4,058 new cases of Covid-19 were recorded in Germany, a significant increase from the 2,828 cases recorded in the 24 hours before.
Andreas Gassen, the head of the country's National Association of Statutory Health Insurance Physicians, said the positivity rate on the 1.1 million daily tests conducted sits at 1.5 per cent, suggesting the rise in overall case numbers is due to better surveillance rather than a rapid spread of infection.
The rise in the number of cases has coincided with the beginning of the autumn holidays for German school children, a time where families traditionally travel. The chancellor, Angela Merkel, has advised people against doing so.
The 16 federal states have tightened rules on domestic travel, with some banning overnight hotel stays for those travelling from risk zones in an effort to deter people from travelling.
A risk zone is classified as an area in which the new infection rate in the past seven days exceeds 50 cases per 100,000 population. The capital, Berlin, crossed this threshold recently, prompting an 11pm curfew to be introduced on pubs and restaurants – the first time in 70 years that the city has placed a closing time on its nightlife.
Mr Spahn reminded Germans that they should continue to wear masks, wash their hands and practice social distancing in order to keep a lid on the outbreak. He encouraged people to download the test and trace app and regularly air out any room they are in.
So far, Germany has recorded 310,144 cases and 9,578 deaths as a result of Covid-19 since the onset of the global pandemic.
The German government has received plaudits globally for its response to the crisis. A recent study by the Barcelona Institute for Global Health ranked its response as the best in Europe.