Veterinary officials in Moscow said Tuesday that an outbreak of the bird flu that is likely to infect humans spread to another region of the country.
The outbreak began in the Novosibirsk region in early July and has killed thousands of domestic fowl. The veterinary service last week identified the virus as the H5N1 strain, which can fatally infect humans, but no human cases have been reported in Russia.
The same strain has been recorded in a village in the adjacent Altai territory, and Yevgeny Nepoklonov, a deputy head of the nation's veterinary service, said on NTV television Tuesday that it has now also been found in a village in the Tyumen region, further west in Siberia.
Domestic fowl also died in the nearby Omsk region, but the strain there hadn't been determined yet.
"A quarantine has been imposed on the settlements affected, and necessary measures are being taken to contain the sources of infection," the veterinary service said in a statement.
The Emergency Situations Ministry said the outbreak already had killed 2,707 domestic fowl, including 325 since Sunday morning.
Authorities in all regions affected by the outbreak have tightened control over poultry farms, disinfecting their workers and checking fowl. The administration of the Novosibirsk region has ordered the killing of 65,000 domestic fowl in all 14 villages affected.
Several regional governments also have imposed bans on poultry sales across provincial borders.
Gennady Onishchenko, Russia's chief epidemiologist, sought to assuage public fears during an inspection trip to the Novosibirsk region Tuesday, saying the outbreak was being successfully contained.
The veterinary service said that the virus apparently had been brought by birds migrating from Southeast Asia. The virus has swept through poultry populations in large areas of Asia since 2003, killing tens of millions of birds and at least 60 people, most of them in Vietnam and Thailand.
Almost all the humans who have died contracted the virus from poultry, but experts worry it could mutate into a more deadly virus that could spread from person to person, the AP reports.