LONDON - The UK government said on Tuesday that cases of bird flu had been confirmed in commercial poultry at premises in Yorkshire, hours after it increased the risk level of the disease from medium to high.

All poultry on the infected premises will be humanely culled, and a three kilometer protection zone had been put in place surrounding the premises, it said in a statement.

Bird flu, or avian influenza, which has killed hundreds of millions of birds around the globe in recent years, has increasingly spread to mammals, raising concerns it may lead to human-to-human transmission.

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Earlier in the day, the government raised its alert level after two different strains of the virus, H5N5 and H5N1, were detected in wild birds in the country over the autumn, according to a government update on Tuesday.

Britain, which had increased the threat level to medium in mid-October, has experienced several bird flu outbreaks over the years, including one in 2021 that was then described as the largest-ever in the country.