An Austrian newspaper reported on Sunday that Russian President Vladimir Putin was suffering from back problems, and that a Viennese orthopaedic expert had travelled to Moscow to treat him.
The Kurier paper did not name the doctor or give the source of the information for its report, which comes amid widespread speculation on the Russian leader's whereabouts.
Putin, who has not been seen in public or on live television broadcasts for more than a week, postponed a meeting with Kazakh and Belarussian leaders last week.
Kremlin spokesman Dmitry Peskov did not pick up his phone when contacted by Reuters to comment on the report.
This evening millions of Russians tuned into a pre-recorded film featuring the Russian President, speaking about Russia's seizure of Crimea.
He said the life of Ukrainian former president Viktor Yanukovich was in danger as a result of the "revolution" that set out to seize power in Kiev.
"For us it became clear and we received information that there were plans not only for his capture, but, preferably for those who carried out the coup, but also for his physical elimination. As one famous historical figure said: no person, no problem," Interfax reported Putin as saying in the film.
Mass protests over Yanukovich's decision to back away from a trade agreement with the European Union in favour of closer ties with Moscow ousted him from power in February last year, and he fled to sanctuary in Russia.
Interfax quoted Putin as saying that saving the life of Yanukovich and his family was a "good deed".
Putin has not been seen in public or on live television since March 5, prompting a wave of savage mockery across the Internet, despite official insistence it was business as usual in the Kremlin.
Independent news broadcaster Dozhd said the Kremlin had declined to comment on its report that Putin had been, not in Moscow, but in Novgorod province at his Lake Valdai residence for the last several days.
The film, to be shown at 22:00 local time across Russia, documents the events that led up to Russia's annexation of Crimea and provided details of Yanukovich's last hours in Ukraine before fleeing to Rostov on Don, in southern Russia.
Putin, speaking in an interview for the documentary "Crimea: Path to the Homeland", said Yanukovich had called on Feb. 21 last year to lay out plans to leave the capital where violent street protests had been raging for weeks.
"I told him my point of view that in such a situation it's best not to leave the capital," said Putin.
From Kiev, Yanukovich left to Kharkiv and then travelled on to Donetsk, where he called Putin asking for help. Putin suggested meeting him personally in Rostov on Don in southern Russia, but Yanukovich's plane was not given permission to leave.
He then travelled to Crimea from where he was spirited to Russia.
Putin, who said he personally organised the annexation of Crimea from Ukraine, also said in the documentary that Russia was ready to bring its nuclear forces to combat readiness if necessary during the change of power in Ukraine and the annexation of Crimea.
The conflict in Ukraine is quickly becoming one of the great tragedies of post-World War II Europe. The vast country of almost 50 million people has been in a state of war for more than a year. The death toll is estimated by the UN to be over 5,000 but it may be considerably higher. And Russia's aggressive interventions, including its annexation of the Crimean peninsula, have transformed the entire continent's security environment.