LONDON (AP) – Britain said Wednesday it was easing a nationwide ban on moving livestock that was imposed after an outbreak of foot-and-mouth disease in southern England, adding there was a low risk of the disease spreading outside the immediate area.

Chief veterinarian Debby Reynolds said farmers outside the six-mile surveillance zone set up around the farms where the outbreaks occurred would be able to send their animals to slaughterhouses as of midnight Wednesday.

Dr. Reynolds said that as a precaution she had ordered the slaughter of livestock on a third farm near one of those affected by the disease. She said tests were being conducted to determine whether any more animals were infected.

Some 214 livestock have already been killed since the disease was identified on a farm southwest of London last week.

Dr. Reynolds said the risk of the disease spreading to the rest of the country from the area around the farms was “low, but not negligible.”

Meanwhile, officials were working to determine whether the foot-and-mouth outbreak came from a high-security government lab near the farms or from a private pharmaceutical company on the same site – and whether its spread was accidental or deliberate.

The country’s health and safety agency said in a report late Tuesday that there was a “strong probability” the outbreak originated at the Pirbright site and was spread by human movement. But the drug company being investigated as a possible source of the outbreak insisted there had been no breach of its biosecurity procedures.

Vaccine-maker Merial Animal Health – the British arm of Duluth, Ga.-based Merial Ltd. – said “intensive internal investigations” had found no evidence of breaches.

“To date, we have not been able to establish any evidence that the virus may have been transported out of our center by humans,” the company said. “We fully support the investigation and will continue to cooperate and provide complete access to our center to enable these investigations to continue.”

The farm where the virus was first discovered last week is four miles from the Pirbright lab complex.

The government’s Health and Safety Executive said there was a “real possibility” the disease was spread by human movement, while the possibility it was transmitted by wind or floodwaters was negligible.

It said there were various potential routes for “accidental or deliberate transfer of material from the site.”

Foot-and-mouth can be carried by wind and on the vehicles and clothes of people who come into contact with infected animals. The disease affects cloven-hoofed animals, including cows, sheep, pigs and goats, but does not typically affect humans.

The Department for Environment, Food and Rural Affairs, or DEFRA, said that officials were investigating a vegetable plot near one of the two infected farms. Newspapers reported that they were looking into the possibility a lab worker had carried the virus to the vegetable patch on boots or clothing.

Environment Secretary Hilary Benn said it was unclear whether the outbreak was the result of accidental or deliberate human contamination.

“The truth is, we don’t know,” he said. “We’re all very, very anxious.”

A group of cows at a second farm was confirmed to have the disease Tuesday. Cranes piled cattle carcasses onto trucks and authorities slightly expanded the protection zone around the second farm, scrambling to halt the spread of the highly contagious virus to other herds in southern England.

News of the second confirmed outbreak fed fears of a repeat of scenes in 2001, when an epidemic led to the incineration of seven million animals on pyres and devastated Britain’s agriculture and rural tourism industries.

China has joined other countries – including America and the 27-nation European Union – in banning imports of British livestock and their products. Britain has voluntarily suspended exports of livestock, meat and milk products in response to the outbreak.