Russian President Vladimir Putin has not been seen in public since 5 March, leading to speculation that he has suffered a stroke or has been ousted in a coup.
Kremlin spokesman Dmitry Peskov has denied reports in Swiss tabloid Blick that Putin was with his rumoured girlfriend Alina Kabaeva, who had given birth to a baby girl in Lugano.
"Putin: Happy new father, not ill?" read the headline in the Swiss press.
"Not true," Peskov told Forbes Russia. "I am planning to appeal to people who have money to organise a competition for the best journalistic hoax."
However, with #PutinIsDead trending amongst Russian Twitter users, the spokesman's frustration ran out when repeatedly questioned about Putin's whereabouts.
"We've already said this a hundred times, this isn't funny anymore."
Peskov declined to comment on a report from independent news outlet Dozhd on Sunday (15 March), that Putin had not been in Moscow for several days.
Putin is due to meet with Kyrgyzstani president Almazbek Atambayev in St Petersburg on Monday, 16 March, but an announcement on Rossiya 24 on Friday referred to the meeting taking place in the past tense.
A Kazakh government official, speaking on the condition of anonymity, told Reuters that Putin may have cancelled the summit with the Belarussian and Kazakh leaders because of illness.
Putin also recently missed a meeting of Russia's annual Federal Security Service, an event he has never been missed before.
John Lough, of policy institute Chatham House said: "Putin has disappeared before, when he was suffering from a slipped disc from a long-standing judo injury,"
"It's normal that he shows signs of stress, he's 62," he told The Independent on Sunday.
Lough added: "In Russia, nobody talks about his problems because he has the image of a tough, energetic president who doesn't get sick. As soon as rumours fly, the Kremlin doesn't do much to address them which gives rise to more rumours, which really shows how this whole operation depends on one person."
Patient or prisoner?
An email sent to the blog Russia Monitor, allegedly signed by an official at the Central Clinical Hospital of the Department of Presidential Affairs in Moscow, stoked rumours of Putin's ill health.
The anonymous official said: "Among the patients of this elite Moscow hospital, where the top leadership of the Russian Federation are registered, there were rumours that Vladimir Putin was diagnosed several days ago with an ischemic stroke."
Even more mysterious is the Instagram post by one of Putin's close allies, Chechen leader Ramzan Kadyrov, who said of the Russian leader: "I am devoted to him as a person. And this regardless of whether he is in his position or not!"
A Daily Mail report concludes that the Russian president is "alive" but "neutralised", amid claims that security chiefs staged a coup in Moscow.
Chairman of the pro-Kremlin national Islamic Committee, Geydar Dzhemal accused former FSB chief Nikolai Patrushev of being behind the plot.
"I think that Putin is neutralised at the moment, but of course, he is alive," said Dzhemal, a Kremlin loyalist. "He is under the control of the power-wielding agencies, who have, in my opinion, organised a coup d'etat."