A man set himself on fire in central Moscow on Sunday after dousing himself with a flammable liquid and was rushed to hospital, police said.
Officers and passers-by put out the blaze within a few moments of him setting himself alight, Moscow's police force said in a statement. It added that the man appeared to have been driven to the act by what it described as personal issues.
The incident took place as thousands of people rallied in Moscow and dozens of other cities across Russia to call for the release of jailed Kremlin critic Alexei Navalny.
There was nothing that immediately suggested a link between the incident and those protests.
In October last year, a Russian journalist died after setting herself on fire in front of the local branch of the interior ministry in the city of Nizhny Novgorod a day after her apartment was searched by police.