Former Russian intelligence officer Sergei Skripal is critically ill after exposure to an unidentified substance in the UK, a source close to the investigation told Reuters.
Skripal is a Russian national convicted of spying for Britain, the BBC reports.
Wiltshire Police said that a man and a woman believed to be in her 30’s were found unconscious at a shopping centre in Salisbury, England, on Sunday.
Skripal was granted refuge in the UK after a “spy swap” between the US and Russia in 2010.
The former intelligence officer was jailed for 13 years in 2006 for passing information of Russian intelligence agents to the UK’s Secret Intelligence Service, MI6.
Both Skripal and the woman were taken to intensive care at Salisbury District Hospital.
Police said the pair did not have any visible injuries but are in critical condition.
“Alongside our partner agencies, we are conducting some extensive inquiries to determine exactly what led to these two people falling unconscious and clarify or not any criminal activity has happened.”
Relations between Britain and Russia have been strained since the murder of ex-KGB agent Alexander Litvinenko in London in 2006, a killing which a British inquiry said was probably approved by President Vladimir Putin.
The Foreign and Commonwealth Office declined to comment when contacted by Euronews.