LONDON (AP) -- British government ministers are attending an emergency committee meeting Wednesday to discuss the mysterious collapse of a former Russian spy and his daughter, who were found slumped on a public bench in southern England after coming in contact with an unknown substance.
Amid speculation about who is behind the suspected poisoning, Moscow said the case was being used to fuel an "anti-Russian campaign" and further strain ties with Britain.
Britain's Home Secretary, the minister responsible for public safety, called a meeting of the government's emergency committee, where senior officials will consider their response. Counterterrorism police are investigating the case, which has left Sergei Skripal, 66, and his 33-year-old daughter, Yulia, in critical condition.
While police say they are keeping an open mind about the case, it has reminded Britain of the 2006 poisoning of former spy Alexander Litvinenko, which was blamed on the Russian state.
Foreign Secretary Boris Johnson told lawmakers Tuesday that the government would act — possibly downgrading England's participation in this year's soccer World Cup in Russia — if Moscow is shown to have been involved in the Skripal case. Johnson warned British officials may not take part in the sport event "in the normal way," but did not elaborate.
The Russian Foreign Ministry said the allegations were intended to "further exacerbate relations between our countries."
"What happened to Skripal has been immediately used to further incite anti-Russian campaign in Western media," ministry spokeswoman Maria Zakharova said.
Skripal, a former colonel in Russia's GRU military intelligence service, was convicted in 2006 of spying for Britain and imprisoned. He was freed in 2010 as part of a widely publicized spy swap in which the U.S. agreed to hand over 10 members of a Russian sleeper cell found operating in America in return for four Russians convicted of spying for the West.
A British inquiry found that Russian agents poisoned Litvinenko by lacing his tea with radioactive polonium-210 and that the killing was probably approved by President Vladimir Putin. Russia has denied any involvement in Litvinenko's death, and this week said it wasn't involved in Skripal's collapse.
Litvinenko's widow, Marina, wrote Wednesday in the Times of London that her husband's case made clear to Britain's emergency services that they need to act quickly when "someone suddenly falls mysteriously ill."
"I am happy my story has raised awareness about the potential danger posed by Moscow, and this could help to save somebody's life," she wrote in an opinion piece.
British counterterrorism specialists have taken control of Skripal's case from local police trying to unravel the mystery of what happened. The matter has not been declared a terrorist incident.
Authorities have cordoned off a new scene in the case, securing Solstice Park, a business park in Amesbury near Stonehenge, the prehistoric monument and world heritage site. Amesbury is about nine miles from Salisbury, the city 90 miles (145 kilometers) southwest of London where the pair were found.
Police also asked members of the public to come forward if they had visited Salisbury's center, a pizza restaurant or a pub where the pair were last seen on Sunday.
Meanwhile, a military research facility is thought to be conducting tests to determine what might have caused the couple to become ill. The Defense Science and Technology Laboratory in nearby Porton Down has state-of-the-art equipment to look for trace amounts of substances.
The local lawmaker for Salisbury, John Glen, told the BBC that the lab "will have taken the substance and will be trying to evaluate what they can, no doubt."
Alastair Hay, a professor emeritus of environmental toxicology at the University of Leeds, said testing could take some time.
"Individuals cannot provide unlimited amounts of blood for testing so investigations will be guided by the clinical team," he said. "If the cause is more unusual, body fluids will require significant cleanup preparation before they can be put in an instrument. So this could take a day or several days."