Denmark has registered 256 cases of infections with B117, a more contagious coronavirus variant first identified in Britain, health authorities said on Saturday.
Denmark extended a lockdown for three weeks on Wednesday in a bid to curtail the spread of the new variant, which authorities expect to be the dominant one by mid-February.
The Nordic country has become a front-runner in monitoring coronavirus mutations by running most positive tests through genome sequencing analysis.
Between mid-November and Jan 10, 256 Danes were infected with the new variant, the State Serum Institute (SSI) said its report published on Saturday.
That corresponds to 1.3% of all positive tests genetically analysed in that period.
In the first week of January, the percentage share of positive tests with the mutation was 3.6%, a growth rate which worried authorities and prompted the lockdown extension.
Preliminary data showed 11 of those infected with the variant had travelled prior to infection, including five in Britain, but SSI said it was unclear whether they had been infected abroad or in Denmark.