With Russian President Vladimir Putin cancelling public engagements and not seen in public in days, the Kremlin has been forced to deny rumours that he is seriously ill.

Putin pulled out of a visit to Kazakhstan yesterday (11 March), with a Kazakh government source telling Reuters that the president had fallen ill.

He also cancelled a ceremony signing a treaty incorporating the South Ossetia region into Russia, reports BY24.org.

News broadcasts and images released by the Kremlin this week show closed doors meetings between Putin and provincial governors, and spokesman Dmitry Peskov brushed aside rumours that Putin was seriously ill, saying he was simply suffering from a "spring fever".

"As soon as the sun comes out in the spring, as soon as spring starts to smell, begin aggravations," Peskov told the Itar Tass state news agency.

"We take these annoyances quietly, and patiently answer all of the questions," said Peskov.

Rumours had begun to circulate online that Putin's illness is more serious than official sources have let on, with some pointing out that he has not been seen in public since 6 March, when he met Italian Prime Minister Matteo Renzi in Moscow.

The Interpreter has translated a report, purportedly published by Russian website Russkiy Monitor, which alleges that Putin had been treated for a stroke, citing an email from a member of staff at an elite Moscow hospital.

The website of Russkiy Monitor is currently down.