They remained in critical condition in a local hospital Friday, poisoned with what authorities say is a rare nerve agent.
Nearly 200 specialists from the RAF and Marines began removing contaminated materials to be sent for analysis at the nearby Porton Down defence laboratory, seven days after the attempted assassination of Sergei Skripal, the Russian double agent.
The defence ministry said 180 soldiers were being dispatched to the normally quiet city of Salisbury in southwestern England, initially to remove "a number of vehicles and objects from the scene". Sgt. Nick Bailey fell ill after visiting Skripal's home, "whereas there was a doctor who looked after the patients in the open" who had not been affected.
"Someone has come onto our soil... has recklessly, brazenly, committed what looks like a very nasty crime, with a nerve agent prohibited, by most worldwide laws... and has potentially put lots of people at risk", he said. In 2010, he was pardoned, released from prison and sent to Britain as part of a spy exchange with Western agencies.
"We have not heard a single fact; we only watch footage on TV, where our colleagues say with serious faces and with gusto that if it is Russian Federation, then a response will follow that Russian Federation will remember forever", he said, according to Interfax.
Police have cordoned off sites, including the cemetery where Sergei Skripal's wife is buried.
REUTERS Peter NichollsUK Police Say Identified Hundreds of Witnesses in Russian ex Spy Poisoning Case
Investigators have been summoned for emergency talks on the crisis in Salisbury, where the fallout from a suspected nerve agent attack continues to widen.
"This was attempted murder in the most cruel and public way", said Rudd, Britain's top police official.
Britain's chief medical officer, Sally Davies, said on March 8 that the general public was not necessarily at high risk, but experts said nerve agents are unsafe and extremely volatile. "But if we are to be rigorous in this investigation, we must avoid speculation and allow the police to carry on their investigation".
Sergei Skripal was said to have spoken to the former intelligence officer in English and Russian and they also discussed his business in Poland.
The incident is drawing comparisons to the case of Alexander Litvinenko, a Russian KGB officer-turned-British intelligence agent and a highly public critic of President Vladimir Putin.
Bob Seely, a Conservative lawmaker and member of the foreign affairs select committee, said the United Kingdom should be cautious about apportioning blame but said circumstantial evidence did raise suspicions of Russian involvement.
Moscow has reacted angrily to the accusations it was involved, with Foreign Minister Sergei Lavrov on Friday dismissing them as baseless "propaganda". One line of inquiry is whether the pair were poisoned at Skripal's suburban house before going out for Sunday lunch and a visit to a pub.