Kremlin says it knows nothing about the unexplained collapse of Sergei Skripal, ex-Russian spy

LONDON — The Kremlin said Tuesday that it has no information about what led to the unexplained collapse of a former Russian agent convicted of spying for Britain, but said it was prepared to help with a case that has baffled investigators.

Sergei Skripal, 66, an ex-Russian military intelligence colonel, and his 33-year-old daughter who was with him, were found unconscious Sunday on a bench in Salisbury, a city about 90 miles west of London, close to the prehistoric stone circle Stonehenge. Police said they had been exposed to an "unknown substance" while out shopping in Salisbury.

Both are in critical condition in intensive care. The BBC reported that the woman with Skripal was his daughter, Yulia Skripal. She lives in Russia.

Skripal was jailed in Russia in 2006 after he confessed to being recruited by British intelligence and supplying information about Russian agents. He was freed in 2010 as part of a U.S.-Russian spy swap and moved to Britain.

The circumstances surrounding Sunday’s incident were still unclear and police urged the public not to speculate, but the incident is reminiscent of the 2006 poisoning death of another former Russian agent, Alexander Litvinenko, after he was exposed to a rare radioactive isotope, polonium-210, at a hotel in London. An official British inquiry concluded in 2016 that Russian President Vladimir Putin probably approved the assassination.

Litvinenko was an outspoken critic of Putin who sought asylum in Britain after he assisted British intelligence and Spanish corruption investigators.

British investigators traced his poisoning to two Russians accused of pouring the radioactive substance into Litvinenko's tea in a posh hotel in Mayfair, an affluent neighborhood in the British capital. The Kremlin adamantly denies the accusation that it was involved in his death.

On Tuesday, Dimitry Peskov, Putin’s spokesman, told reporters Skripal's case was a "tragic situation but we don't have information on what could have led to this." He said Britain had not requested its help but "Moscow is always ready to cooperate."

Mark Rowley, Britain’s top counter-terrorism officer, told BBC radio police and intelligence officers from his agency were speaking to witnesses, taking forensic samples at the scene and doing toxicology work to try to get to answers.

"We have to remember: Russian exiles aren’t immortal, they do all die and there can be a tendency to conspiracy theories. But likewise we have to be alive to the fact of state threats," Rowley said, before referring to the murder of Litvinenko.

In a separate statement, Rowley's office said the case has not been declared a terrorist incident and it is keeping an open mind about what happened.

A number of outspoken critics of Putin have been killed or died in mysterious circumstances, including journalists, opposition politicians and exiled tycoons.

Putin is running for re-election March 18 and is the overwhelming favorite to win.

Britain's Foreign Minister Boris Johnson warned Russia that the country would respond "robustly" if evidence emerged of Moscow's involvement in the Skripal case.

“I say to governments around the world that no attempt to take innocent life on U.K. soil will go either unsanctioned or unpunished,” he said.

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Dorell reported from Washington, D.C.