The research laboratories, one run by the government's IAH and the other owned by Merial Animal Health Ltd, a US-French company, are located about 8km from where the virus infected the cattle.
The report also said: "Release by human movement must also be considered a real possibility. Further investigation of the above issues is required as is being urgently pursued."
Both laboratories, which conduct research and develop vaccines against foot and mouth, handle the exact, rare strain of the virus that struck the herd, a strain isolated by British scientists 40 years ago.
A second outbreak of foot-and-mouth disease in southern England was announced on Tuesday.
Hilary Benn, the environment minister, said that the second infected herd of cattle to be destroyed were within the 3km protection zone set up around the farm where the first outbreak was discovered.
This second outbreak, 50km southwest of London, occurred about 6km from a laboratory that produces vaccines containing an identical strain of foot-and-mouth virus, officials said.
The latest outbreak has brought back memories of 2001, when more than six million animals had to slaughtered costing the agriculture and rural tourism industries an estimated $17bn.
"We were starting to think this virus had been contained and maybe we were going to be getting back to normality in a few weeks," Laurence Matthews, who owns the farm where the second infected herd grazed, said on Tuesday.
"Now this has set us back again and most farmers, and I've been speaking to a few, are very, very scared."
The outbreaks come amid widespread flooding, and investigators have been considering the possibility that the flooding might have helped spread the virus.
Debby Reynolds, Britain's chief veterinary officer, said inspectors doing routine checks found clinical signs suspected of being foot-and-mouth disease not far from the first farm.
The strain had not been seen in animals for a long time but was used to produce vaccines, she said.
She said about 50 cattle from the second herd were slaughtered on Monday night as a precaution.
"We have been able to rapidly identify this suspect case and take appropriate action swiftly," she said in a statement released by the department for food, environment and agriculture.
"I continue to urge all animal keepers to be vigilant for signs of disease and practice strict biosecurity."
The foot-and-mouth virus affects cloven-hoofed animals and is airborne, making it highly contagious.
Tracing the source
Biosecurity experts are focusing on two laboratories as the possible source of the outbreak.
The government-run Institute for Animal Health and a facility operated by Merial Animal Health, a US-French company, both handle foot-and-mouth virus samples.
Both have stocks of the uncommon strain of foot and mouth that was found to have infected the first herd of cattle.
|Investigators are looking at whether flooding |
may have spread the virus [EPA]
Merial made a batch of vaccines containing that strain of the virus last month.
Both laboratories have since issued statements denying there was any breach of their biosecurity measures.
Government inspectors are expected to issue a report of their findings on Tuesday after conducting a search of both laboratories.
A nationwide ban on all livestock movement is expected to last for several weeks at least, raising concerns of a deep economic impact on the meat farming industry that is worth more than $1bn a year.
The European Union has endorsed Britain's decision to ban meat and dairy exports.