Ever since he launched his invasion of Ukraine in February, there have been constant reports that Vladimir Putin is suffering from some kind of illness.
The health of the Russian president, 70, has been the subject of speculation, including claims he has cancer and Parkinson's disease.
The Kremlin has been forced to make repeated denials that Putin is sick, as their leader deals with the backlash from the international community and criticism from within his own country over his invasion of Ukraine. US intelligence officials appear divided over reports that Putin is unwell.
Vladimir Putin's health explained in 9 points
Where have the rumours come from? In May, leaked audio emerged in which a Kremlin-linked oligarch appears to suggest Putin has blood cancer. The recording was obtained by New Lines magazine, and contained the claim the president was "very ill".
This came after speculation about Putin's health following the Moscow Victory Day Parade. The Russian leader was photographed with a blanket over his legs at the event, an annual military show of strength in the Russian capital. Other photos appear to show track marks on his hands, which some commentators have speculated could come from intravenous drips.
Former chief of the British Army, Lord Richard Dannatt, also said earlier this month that the state of Putin's hands suggest he may be unwell. He told Sky News: "Keen observers now are noticing that his hands are looking pretty black on top, which is a sign of injections going in when other parts of the body can't take injections."
There are further reports that Putin has Parkinson's and pancreatic cancer. Earlier this month, The Sun reported that it had seen Russian intelligence documents that claim Putin has been diagnosed with early stage Parkinson's and pancreatic cancer, with the condition "already progressing".
How good is the evidence? In June, defence and security expert Professor Michael Clarke said there was "no convincing evidence" that Putin has Parkinson's or cancer. He said: "He is known to hit the Botox quite heavily... He moves around with doctors, there's known to be a little team of doctors who are never far away, and it's said that he leaves meetings at frequent intervals to go and consult with somebody. I suspect that he's only a hypochondriac, to be honest."
What has US intelligence said? American intelligence officials told Newsweek in June that they believed Putin was treated for "advanced cancer" in April. However, in July, CIA director William Burns said there was no intelligence that Putin is mentally unstable or in poor health. He told a security conference in Colorado: "There are lots of rumours about president Putin's health and as far as we can tell he's entirely too healthy."
And what has Ukraine said about it? In May, Ukraine said it believes that Putin has cancer. Kyrylo Budanov, head of the main directorate of intelligence of the ministry of defence of Ukraine, told Ukrainian news outlet Pravda that the Russian president has "several illnesses". He said: "Yes, we fully confirm this information, that Putin has cancer. But it’s not worth hoping that Putin will die tomorrow. He still has at least a few years left. Whether we like it or not, that’s the truth."
What about the Kremlin? Russia's foreign minister Sergei Lavrov has denied that Putin is ill. He told French television channel TF1: "I don’t think that sane people can see in this person signs of some kind of illness or ailment." Lavrov pointed out that Putin was making regular appearances in public. In July, Kremlin spokesman Dmitry Peskov said: "Everything is fine with his health."
What does this mean for Russia? Former British intelligence officer Christopher Steele said in June that Putin could become medically incapacitated within three to six months and then ousted as Russian leader. Steele told BBC Radio 4’s The World at One: “This is a strongman regime where people have to have fear of the leader and if the leader is incapacitated medically then there will be a move against him, I'm sure.”