British authorities are testing for the outbreak of another possible case of foot and mouth disease, several kilometers from where two outbreaks were found in cattle last week.
Officials imposed a three-kilometer control zone Friday around a British farm suspected of a new case of the disease.
Just days after authorities thought they had contained an outbreak of foot and mouth disease, the new possible case is causing fears it is spreading.
Though the case is not confirmed, Britain's chief veterinarian Debby Reynolds released a statement saying the outbreak is "a developing disease situation." Officials are waiting for test results.
Health authorities had thought the virus was contained, and on Thursday eased restrictions on allowing farmers to transport livestock.
Almost 600 animals have been destroyed.
Foot and mouth disease is not harmful to people. However, farmers are afraid of a repeat of the outbreak in 2001 when almost seven million animals were slaughtered, devastating Britain's agriculture industry.
Health investigators believe there is a strong possibility the latest outbreak started in a research laboratory close to the farms.
One of the labs, the privately run Merial Animal Health laboratory, rejects the claim, and says there is no evidence the virus was transported out of its center by humans.
The disease affects cloven-hoofed animals such as cows and pigs and is spread mostly through direct contact between animals or through contaminated feed.
Some information for this report was provided by AFP and AP.