Protests are being held in about 30 Russian cities to express anger at proposals to raise the pension age.
The plan, announced the day the football World Cup began, would see the age raised gradually from 60 to 65 for men, and from 55 to 63 for women.
The government says the changes are needed to cope with a shrinking workforce having to provide for an increasing number of retirees.
But unions warn many people will not live long enough to claim a pension.
Russian men have a life expectancy of 66 while for women it is 77, the World Health Organization says.