Denmark's health authorities said Sunday the country had seen a worrisome increase to 183 confirmed cases of the Omicron variant of Covid-19.
The number represented a tripling of confirmed cases in 48 hours, from 18 confirmed and 42 suspected cases on Friday, according to data from the SSI public health institute.
The European Centre for Disease Prevention and Control (ECDC) had previously tallied just 182 cases across all of the European Union, plus Norway and Iceland.
Denmark is one of Europe's most advanced countries in sequencing of coronavirus variants.
It often detects more cases more quickly than its neighbours, which does not necessarily indicate higher rates of infection.
The SSI chief said the increase in Omicron cases was nevertheless "concerning", adding that "there are now chains of infection where the variant is found in people who have not travelled abroad or been in contact with travellers".
Also on Sunday, the ECDC said Omicron had been reported in 17 of the countries it serves.
"The majority of confirmed cases have a history of travel to countries in Africa, with some having taken connecting flights at other locations between Africa and Europe," the ECDC said on its website before the Danish announcement.
Nevertheless, "several EU/EEA countries (Belgium, Germany, Spain) detected cases without an epidemiological link to areas where community transmission of the Omicron variant is documented or presumed," it added.
"This indicates that undetected community transmission could be ongoing in these countries."