British media reported todaythat a former Russian spy was in critical condition after coming into contact with an "unknown substance," a case that immediately drew parallels to the poisoning of former Russian agent Alexander Litvinenko.
Authorities did not identify the man, saying only that he and a woman had been found unconscious on a bench in a shopping mall in Salisbury, an English city about 145 kilometers west of London.
But the Press Association and other British media identified him as Sergei Skripal, 66, who was convicted in Russia on charges of spying for Britain and sentenced in 2006 to 13 years in prison.
Skripal was freed in 2010 as part of a US-Russian spy swap.
Wiltshire Police, which is responsible for the Salisbury area, only identified the man and woman by their approximate ages and said they appeared to know one another and "did not have any visible injuries."
"They are currently being treated for suspected exposure to an unknown substance. Both are currently in a critical condition in intensive care," police said in a statement.
Eyewitness Freya Church told the BBC it looked like the two people had taken "something quite strong".
"On the bench there was a couple, an older guy and a younger girl. She was sort of leaned in on him. It looked like she had passed out, maybe, Church said.
"He was doing some strange hand movements, looking up to the sky," she said.
Public Health England said in a statement that it had only limited information about the patients, but there "doesn't appear to be any further immediate risk to public health."
"PHE understands that those exposed to the substances have been decontaminated," the health agency said.
Skripal served with Russia's military intelligence, often known by its Russian-language acronym GRU, and retired in 1999. He then worked at the Foreign Ministry until 2003 and later became involved in business.
After his 2004 arrest in Moscow, he confessed to having been recruited by British intelligence in 1995 and said he provided information about GRU agents in Europe, receiving over $100,000 in return.
At the time of Skripal's trial, the Russian media quoted the FSB domestic security agency as saying that the damage from his activities could be compared to harm inflicted by Oleg Penkovsky, a GRU colonel who spied for the United States and Britain. Penkovsky was executed in 1963.
Skripal was pardoned and released from custody in July 2010 as part of a US-Russian-spy swap, which followed the exposure of a ring of Russian sleeper agents in the United States.
The circumstances surrounding Monday's incident were still murky, but the case had immediate resonance in Britain; former Russian agent Alexander Litvenko died after drinking radioactive tea in a swanky London hotel in 2006.
In a report published in 2016, a British judge wrote that Russian President Vladimir Putin probably approved the assassination carried out by the country's security services.