The World Health Organisation is looking at biosecurity around mink farms in countries across the world to prevent further "spill-over events" after Denmark ordered a mink cull because of an outbreak of coronavirus infections in the animals.
Maria van Kerkhove, the WHO's technical lead for COVID-19, told a briefing in Geneva on Friday that transmission of the virus between animals and humans was "a concern".
But she added: "Mutations (in viruses) are normal. These type of changes in the virus are something we have been tracking since the beginning."
The risk was much lower in other farm animals than mink, which appear to be much more susceptible to infection, a second WHO expert said.
"We are working with regional offices... where there are mink farms, and looking at biosecurity and to prevent spill-over events," van Kerkhove said.
Denmark said this week it plans to cull its entire mink population and announced strict new lockdown measures in the north of the country to prevent a mutated coronavirus from spreading in the animals and to humans.
It has raised concerns that the mutations could affect the potential efficacy of COVID-19 vaccines in development.
Soumya Swaminathan, the WHO's chief scientist, said on Friday, however, that it is too early to jump to conclusions about the implications of mutations in the virus found in mink.
"We need to wait and see what the implications are but I don't think we should come to any conclusions about whether this particular mutation is going to impact vaccine efficacy," she said.
"We don't have any evidence at the moment that it would."
Denmark's State Serum Institute, which deals with infectious diseases, said a mutated strain of the SARS-CoV-2 coronavirus had been found in at least 214 people and on five mink farms.
Kerkhove said Denmark's decision to cull its mink was aimed at preventing the establishment of "a new animal reservoir for this virus".
Mike Ryan, the WHO's top emergencies expert, said the WHO would complete a risk assessment of the incident and share it with WHO members within hours.
Coronavirus is thought to have first jumped from animals to humans in China, possibly via bats or another animal at a food market in Wuhan, although many outstanding questions remain.
Other mammals have been known to catch it such as cats.
Others, such as mice and ferrets, are being intentionally infected with it for medical research.
"There's always the potential that this can come back to humans," Ryan said.
"That is a concern because mammal species like mink are very good hosts and the virus can evolve within those species especially if they are in large numbers packed closely together."
But Ryan added that other farm animals, such as pigs and poultry, had "very strict" biosecurity in place to prevent viruses jumping the species barrier.
Sweden's agriculture ministry confirmed on Friday that authorities had detected an outbreak of coronavirus at 10 mink farms in the southern region of Blekinge.
Globally, more than 48.85 million people have been reported to be infected by the coronavirus and 1,236,320 have died.
In Italy, anti-lockdown protesters in a coronavirus-weary country continued to voice their anger as regional restrictions were beefed up on Friday.
Meanwhile, India recorded 47,638 new cases of the coronavirus to take its total to 8.4 million.
Deaths rose by 670 in the last 24 hours, driving total fatalities to 124,985 on Friday, health ministry data showed.
India has the world's second-highest caseload behind the United States.
Even though the country has registered a steady dip in cases since mid-September, its capital is posting a surge in infections.
New Delhi recorded nearly 6700 new COVID-19 cases in the last 24 hours, the second-highest single-day spike since the pandemic began.
In more positive news, Belgian authorities are reporting a slowdown in COVID-19 infections, bringing tentative hope that the country - which still has one of the highest infection rates in Europe - could have passed the peak of the second wave of the pandemic.
Yves Van Laethem, a member of the Belgian specialist committee for COVID-19, said: "For a few days now we can, fortunately, see figures heading in the right direction, we can at last start to trace the peak of this second wave."