A laboratory in Germany has confirmed that bird flu has been found in a cat.
However, reports are unclear whether the tests have yet confirmed the H5N1 strain of the virus in the animal.
It is believed to be the first case in Europe where the virus has crossed to a different species.
Cats were first infected with bird flu in Asia in 2004 following
the outbreak of the deadly form of bird flu in 2003.
The cat was found on the northern island of Ruegen, where most cases of H5N1 in birds in Germany have been found.
In Sweden, officials have reported an 'aggressive' strain of bird flu, believed to be of the H5 group, after tests on four ducks.
Following that announcement, Latvia and Finland both ordered poultry and domestic birds to be kept indoors.
Thirty countries are now reported to have banned imports of French poultry and poultry products after France became the first European country to report infection with H5N1 among domestic fowl.
And a state of emergency has been declared in Krasnodar in southern Russia, after a total of more than 103,000 birds died in the past week as a result of bird flu.
Tests are still under way to determine whether this was the H5N1 strain.
The World Organisation for Animal Health, the OIE, earlier said that the H5N1 strain would very likely spread to domestic poultry in other European states.
Chief veterinary officers from more than 50 countries have continued their meeting at the Paris headquarters of the OIE to co-ordinate their response to the virus.
Experts have expressed fears that H5N1, which has killed more than 90 people since 2003, may mutate into a form that can pass between humans.
