In the United States, still dealing with its first wave as infection rates have climbed since June, President Donald Trump’s national security adviser, Robert O’Brien, became the most senior official to test positive. The White House said Trump had not interacted with him in days and was not at risk.
Surges were reported in several countries that previously appeared to have the virus under control.
Australia recorded a record daily rise. Vietnam was forcing tens of thousands of tourists to evacuate the central city of Danang. Mainland China, where the virus first emerged late last year, confirmed the most locally transmitted cases since early March.
Hong Kong banned gatherings of more than two people, closed restaurant dining and made face masks mandatory in public.
A surge of new infections in Spain, another early epicentre of the pandemic, prompted Britain on Saturday to order all travellers from there to quarantine for two weeks, undoing months of preparation for Europe’s reopening to tourism.
The World Health Organization (WHO) said travel restrictions were not a long-term answer. It said proven strategies such as social distancing and face covering must be employed to halt the virus spread.