Sources told the British former spy that President Putin is sick.
Christopher Steele, who led MI6's Russia desk and worked as a spy in Moscow for years, told Sky News that Putin is seriously ill.
For months, there have been claims about the leader's health. Major General Kyrylo Budanov, the head of military intelligence in Ukraine, told Sky that Putin is sick and in a bad psychological and physical condition.
Budanov said that the illness has incited plans for a coup in Russia.
Steele said in an interview with Sky that Putin's health is an element in his decision-making.
It is not clear what this illness is, whether it is terminal or not, and I think it is part of the equation.
New Lines Magazine published the claims of an anonymous Russian billionaire who said that Putin is very ill with blood cancer.
Russian investigative news outlet Proekt wrote in early April that the leader has received dozens of visits from a thyroid cancer specialist.
There is a serious concern that Putin is suffering from dementia and Parkinson's disease, according to a former KGB agent.
The leader's bloated face and images of him appearing to steady himself while seated in an April meeting with his Defense Minister were the subject of weeks of tabloid speculation.
Steele is the author of an intelligence dossier that made a number of claims about Trump, including the existence of a Russian videotape that was said to have incriminating material about Trump before he became a politician.
No evidence of the "pee tape" has been found, and other aspects of the report's credibility have been questioned.
Steele worked as a spy in Moscow for three years in the 90s and was chief of the Russia desk for MI6 between 2006 and 2009.