British scientists worked Saturday to trace the source of a foot-and-mouth disease outbreak on an English farm and authorities imposed a nationwide ban on moving livestock in a bid to stop the spread of the highly infectious virus that devastated the farming industry six years ago.

As officials tried to stop the disease spreading, and farmers waited and worried, the government said the European Union would ban livestock imports from Britain in response to the outbreak.

"There will be a ban on exports within the European Union. That is automatically imposed as a result of the finding of foot-and-mouth disease," Cabinet Office Minister Ed Miliband told the British Broadcasting Corp.

In a statement, the European Commission said it would adopt an emergency decision Monday "concerning restrictions on the movement of animals and the dispatch of products from the U.K."

The financial cost to Britain was likely to escalate as more countries followed suit. Japan said it had banned British pork imports following the outbreak. British beef has been banned in Japan since the 1990s as a result of mad cow disease.

The case is the first in Britain since 2001, when a foot-and-mouth epidemic led to the slaughter of 7 million livestock. Many of the carcasses were burned on huge pyres that dotted the country, and large swaths of countryside were declared off-limits to visitors, damaging tourism.

Then, the government was accused of reacting too slowly, allowing the highly infectious disease to spread.

Prime Minister Gordon Brown and Environment Secretary Hilary Benn cut short their holidays when they learned of the new outbreak. They attended a meeting of the government's crisis committee, COBRA, on Saturday.

The Department of Environment, Food and Rural Affairs, or DEFRA, said animals on a farm near Wanborough, about 30 miles southwest of London, had tested positive for the disease, which affects cows, horses, sheep and pigs. It does not affect humans.

DEFRA did not immediately say how many animals were infected, but said all animals on the farm would be slaughtered and incinerated. Officials stressed there was no plan to burn the carcasses on pyres.

At the infected farm, veterinary workers in protective white coveralls rounded up cattle and put them into pens. Vehicles entering and leaving the farm were sprayed with disinfectant.

Authorities imposed a 2-mile radius protection zone and a surveillance zone of 10 kilometers (6 miles) around the farm. DEFRA said a ban was also imposed nationwide on moving all hooved animals, including pigs.

Scientists were carrying out tests to determine the strain of the disease, and whether vaccination would be possible to halt its spread.

The government was criticized for not using vaccines in the 2001 epidemic. A report on the epidemic by a senior scientific body, the Royal Society, concluded that vaccination should be a major tool of first resort in the event of future outbreaks.

"The laboratory tests are already under way and the earliest possible information will probably come during the later part of today," said the country's chief veterinarian, Debby Reynolds.

She said investigations would try to determine whether the virus reached Britain through the illegal movement of animals, on the wind or by accidental contamination.

Reynolds said it was too early to say how far the disease might spread.

Nearby farmers were worried, but hopeful that quick action would contain the disease.

"We are keeping our fingers crossed but there is really nothing we can do about it except wait," said Michael More-Molyneux, whose farm is about 5 miles from the infected site.

The 2001 outbreak started with a pig herd in northern England and spread to cows and sheep. It eventually infected more than 2,000 farms and shut Britain out of the world's livestock export markets.

Huge pyres of culled livestock belched smoke and the countryside was effectively shut down, devastating the tourist industry. British taxpayers shelled out more than $2 billion for compensation, disinfecting, veterinarians and the slaughter. The total cost to the country was estimated at $16 billion.

It was almost a year before Britain was declared free of the disease, and months more before British exports were allowed to resume.

Tim Bonner, spokesman for the Countryside Alliance, said farmers were extremely worried by the latest outbreak.

"Farmers around the country will be hoping and praying that this is an isolated incident and that the disease is not already widespread, because last time when we found out about it, it was already everywhere," he said. "We hope and pray that the lessons from last time have been learned."