Debby Reynolds, chief veterinary officer, said an interim report on the outbreak "indicates that infection may be contained to the Surrey area.''

Precaution

The department for environment, food and rural affairs (Defra) said that animals slaughtered on Wednesday as a precaution on a farm within the protection zone around the original outbreak did not have foot and mouth disease.

The farm was adjacent to one of two properties where livestock had tested positive for the disease.

Reynolds said late on Thursday that cows in a second area of Surrey had shown "mild clinical signs of infections,'' announcing that a new three-kilometre exclusion zone had been set up around a farm previously unlinked to the outbreak.

The new suspected case is around 15km away from two farms where cases have been confirmed and a third plot where cattle have been killed as a precaution.

The farmer at the site, near the village of Wotton, said he had called a veterinarian after noticing signs of illness in some of his calves, and because he had links with the area where the earlier outbreaks occurred. 

"The vet was absolutely sure this was not foot and mouth,'' Laurence Matthews said.

Livestock bans

Several countries have banned imports of British livestock and Britain has voluntarily suspended exports of livestock, meat and milk products and since the outbreak was identified last week.

Brown said a national ban on the movement of livestock would stay in place "until we are absolutely sure that we have contained and controlled the disease".
   
The movement ban was eased on Thursday to permit farmers outside the infected area to move animals for slaughter.

Brown also promised swift compensation for farmers affected by the outbreak.
   
"We will extend the compensation beyond the statutory requirements to include cleanup costs and I hope that payments will be made in the coming days to all farmers in the infected areas who have suffered these losses," he said.
   
Farmers say the restrictions are costing them $3.6 million a day.

Britain's health and safety agency says there is a "strong probability'' that outbreak originated at the Pirbright laboratory southwest of London and was spread by human movement.