German health experts warned on Thursday that the coronavirus could "spread uncontrollably" in the country, as infections surged across Europe and governments prepared to renew some lockdown measures.
In Belgium, Brussels' crowded bars and cafes were shut for a month, a return to the stricter protocols imposed at the height of the epidemic in March and April.
And in France, officials were to apply tighter restrictions in several major cities, two days after a maximum alert protocol went into force in Paris.
Across the Atlantic, President Donald Trump's handling of the pandemic continues to dominate the US election, with the Democrats' Kamala Harris accusing him of overseeing "the greatest failure... in the history of our country".
Germany's response to the crisis has been held up as a relative success, but officials are now raising the alarm over a "worrying jump" in coronavirus cases.
The number of new daily infections in Germany soared past 4,000 for the first time since early April.
"We don't know how the situation in Germany will develop in the coming weeks," warned Lothar Wieler, the head of Germany's Robert Koch Institute for disease control.
"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."
The alarming jump in cases coincided with autumn school holidays in many parts of Germany, prompting calls from Chancellor Angela Merkel's government for citizens to avoid travel abroad.
Health Minister Jens Spahn said many young people were "partying, travelling, thinking they are invincible".
"But they're not," he said, urging them to think of the risk they pose to elderly relatives.
The number of daily coronavirus infections came in at 18,746 in France on Wednesday, a record since widespread testing began.
In Paris, bars and cafes were ordered to close on Tuesday for two weeks to slow the spread, just over a week after new restrictions were imposed on Marseille and the overseas region of Guadeloupe.
Health Minister Olivier Veran is expected to announce later that tighter rules will be imposed in other cities.
Bars were also ordered to close on Thursday in the Belgian capital Brussels, home to the headquarters of the European Union and NATO.
Restaurants will remain open under strict social-distancing rules, but outdoor drinking and cafes will close after both new cases and hospitalizations surged to their highest levels since April.
Scotland imposed two-week ban on pubs in its main cities of Glasgow and Edinburgh on Wednesday, increasing pressure on Prime Minister Boris Johnson's UK government to take similar steps in England.
But stark warnings from health experts about the rise in cases are balanced against rising opposition to lockdowns in many countries, from hard-pressed businesses and sceptical protesters.
In Spain, Madrid's top regional court on Thursday rejected a partial lockdown imposed on the capital's 4.5 million residents at the weekend.
The ruling stated that the order intruded on "the rights and fundamental freedoms" of Madrilenos.
Tensions over the virus also took centre stage at the US vice-presidential debate between the incumbent Mike Pence and Kamala Harris, running mate to Trump's Democratic challenger Joe Biden.
The Covid-19 illness has killed more than 210,000 people in the United States, more than in any other country, and Trump has just emerged from hospital after catching a disease he once dismissed as harmless.
"The American people have witnessed what is the greatest failure of any presidential administration in the history of our country," said Harris.
"The president said it was a hoax. They minimized the seriousness of it," she declared. Pence insisted Trump had put "the health of America first" and accused Biden of copying his Covid plan.
The novel coronavirus has killed more than a million people since the outbreak emerged in China last December, and the lockdown measures adopted by many governments have battered the world economy.