Denmark, the world's biggest producer of mink fur, is to cull all of the country's minks after a mutated version of the new coronavirus was detected at mink farms and had spread to people.
The mutation "could pose a risk that future (coronavirus) vaccines won't work the way they should," Prime Minister Mette Frederiksen told a press conference.
"It is necessary to cull all the minks."
Denmark's police chief Thorkild Fogde said they would start the culling as "soon as possible," but conceded that with 15 million to 17 million minks spread over 1,080 farms it was "a very large undertaking".
The novel coronavirus has been detected at 207 mink farms, including some cases with a mutated version that has been confirmed to spread back to humans.
Health authorities have also concluded that the mutated virus has "is not inhibited by antibodies to the same degree as the normal virus".
"Studies have shown that the mutations may affect the current candidates for a Covid-19 vaccine," Health Minister Magnus Heunicke said.
"It is a threat to the development of coronavirus vaccines. That is why it is important that we make a national effort," he added.
While the majority of cases had been observed in the northern part of the Jutland region, all minks in the country would still be culled.