There are fears foot-and-mouth virus is spreading as British authorities conduct tests Friday to determine whether cattle who fell ill not far from the original site of the outbreak last week are suffering from the same disease.

A new three-kilometre exclusion zone was set up around the original site of the outbreak after cows in a second region nearby showed "mild clinical signs of infections" according to Chief Veterinary Officer Debby Reynolds.

The sick cattle are just 15 kilometres away from two farms where cases have been confirmed and a third site where cows have been killed as a precaution.

However British Prime Minister Gordon Brown said the disease had been contained and there was little risk the virus could have spread.

"We have restricted the disease to a limited area of this country," Brown said. "The risk of it spreading out of these areas is low, if not negligible."

Reynolds said an interim epidemiology report on the outbreak "indicates that infection may be contained to the Surrey area."

This newest outbreak, located in the southern England county of Surrey, is a "developing disease situation," said Reynolds. A farmer working the site called the veterinarian after he noticed some of his animals developing symptoms of illness. He said he had links with the area where the original outbreak took place.

Though authorities had yet to confirm if the symptoms are in fact a result of foot-and-mouth, news of the sick cows sparked concerns the virus was uncontained. Farmers faced a disastrous situation in 2001 when seven million animals had to be killed and incinerated on pyres.

Lawrence Matthews, the farmer who called the vet, told The Associated Press he is hopeful.

"The vet was absolutely sure this was not foot-and-mouth," he said, adding he will know for sure later Friday when the results are expected to come in. "Hopefully, they will not show foot-and-mouth at this farm."

Reynolds said containing and eradicating the virus has been a priority.

"This is why we have moved swiftly to put in place a temporary control zone while we investigate this development," she said in a prepared statement released Thursday.

If it is indeed foot-and-mouth disease, it could have a devastating impact on the economic success of Britain's agricultural industry. Several countries have already moved to ban imports of British livestock while Britain started to voluntarily suspend exports of its livestock, milk and meat products since the outbreak was first identified last week. More than 570 cows in the country have also been destroyed as a precaution.

However, believing the virus had been contained, British officials relaxed their nationwide ban on moving livestock.

"People are going to be even more apprehensive than they have been throughout the whole of this,'' Hugh Broom, of the National Farmers' Union, told British Broadcasting Corp. television. "It will be worrying for members here and farmers elsewhere in the country.''

It is believed the virus was transported by human movement from the Pirbright laboratory southwest of London, as foot-and-mouth can be passed along by wind, or on the cars and clothes of people who came into contact with sick animals.

There is a "strong probability" the outbreak originated form that site, said Britain's health and safety agency, but there was no evidence of a security breach in biosecurity or any sign of system failure in the facility's water system.

With files from The Associated Press