And now some observers – experts and social media users – have suggested that the Russian president’s health is failing.
The Daily Telegraph published a piece entitled Five reasons to suggest ‘puffy-faced’ Putin could be seriously ill.
Where are these rumours coming from, and have they been substantiated?
Does Vladimir Putin have cancer?
The claim that Putin has cancer and that his condition prompted the invasion of Ukraine was made by a senior Royal Navy admiral earlier this week.
Speaking to children at Portsmouth Grammar School on March 4, former pupil and Falklands veteran Rear Admiral Chris Parry said: “He has been using these very long tables to interview people.
“I think his immune system might be suppressed at the moment. So he is a man in a hurry."
The remarks - referring to bizarre pictures of Putin meeting French President Emmanuel Macron across a huge table – were reported by our sister title, The Portsmouth News.
Parry continued: "What I think will happen is he will occupy Ukraine to the east of the Dnieper [river], he will totally occupy this region known as “New Russia” across the bottom of the country, cutting Ukraine off from the Black Sea, and he will leave that rump of the north west, to the west of Kyiv, to it’s own devices as long as it stays neutral."
There has been no official confirmation, at home or abroad, about the state of Putin’s health.
Why do people think people think President Putin is ill?
The Daily Star quotes an unnamed US intelligence source supporting the claims about Putin’s health who claimed his ‘puffy face’, seen in recent photographs, is a side-effect of chemotherapy drugs or steroids.
The ex-military intelligence officer now working at the Pentagon told the Reach title that analysts have been studying Putin, 69, and believe he is gravely ill.
The source said: “In the past we have seen him smile, but in 2022 there are few pictures of him looking happy.
"His look suggests he is in pain and our people suggest his angry look is most likely as a result of him being in agony.
“Our people are confident he is ill – he is concerned about Covid as he keeps his staff at a distance.”
The Sun quotes social media observations that the Russian leader looks ‘ashen and bloated’ in official pictures released by the Kremlin.
Putin has built an image as a strong man figure leading Russia, and has posed for pictures competing in judo, and shirtless on a horse.
But on March 1, official pictures of the president meeting St Petersburg governor Alexander Beglov sparked fresh claims about his health.
What have experts said?
Fiona Hill, a senior fellow in the Center on the United States and Europe in the Foreign Policy program at Brookings, was quoted by Politico saying: "Putin’s not looking so great, he’s been rather puffy-faced.
"We know that he has complained about having back issues. Even if it’s not something worse than that, it could be that he’s taking high doses of steroids, or there may be something else. There seems to be an urgency for this that may be also driven by personal factors.”
Hill, who served as national intelligence officer for Russia and Eurasia at The National Intelligence Council, continued: “He may have a sense that time is marching on — it’s 22 years, after all, and the likelihood after that kind of time of a Russian leader leaving voluntarily or through elections is pretty slim.
"Most leaders leave either like Belarusian president Alexander Lukashenko thought that he might leave, as the result of massive protests, or they die in office.
“The only other person who has been Russian leader in modern times longer than Putin is Stalin, and Stalin died in office.”
Republican senator Marco Rubio is another prominent figure who has claimed ‘something is off’ with President Putin.
Mr Rubio is the ranking Republican member of the Senate Intelligence Committee.
Senator Rubio said: "I wish I could share more, but for now, I can say it’s pretty obvious to many that something is off with Putin.
"He has always been a killer, but his problem now is different and significant."
Mr Rubio later added Mr Putin "appears to have some neuro/physiological health issues."
The Daily Mail reported Senator Rubio saying ‘[Putin] is older now. His time is running out on this earth. He knows that.”
Have Putin or the Kremlin responded?
The Kremlin did previously rubbish previous claims that Putin was suffering from Parkinson’s disease as ‘absolute nonsense’.
In November 2020, Professor Valery Solovei – a former historian at the Moscow State Institute of International Relations – reportedly said Putin was suffering from both cancer and Parkinson’s.
His conclusion was that the President would have to quite over health fears. The Kremlin denied the claims and Professor Solovei was later detained at a protest in Moscow.