Russia's prime minister says President Vladimir Putin has no "serious" health problems.
Before a visit to Finland, Dmitry Medvedev told Finnish media on November 14 that "each of us has certain petty things to take care of."
Putin's spokesman, Dmitry Peskov, acknowledged two weeks ago that the president strained his back while exercising.
Putin has canceled several foreign trips in recent weeks and spent most days working at his suburban residence, rarely visiting the Kremlin.
Earlier this month, some Russian media reported Putin had injured his back in a widely publicized flight with Siberian cranes in a motorized hang-glider in September.
Putin's spokesman has denied that claim.
Based on reporting by AP and Interfax