A bomb blast has badly damaged the front facade of a state Pension Fund office in the Russian city of Kaluga, local media reports say.
The apparent attack came amid public anger and frequent street protests over the government's plan to raise the retirement age.
Media outlets cited unidentified law enforcement officials in the city 150 kilometers southwest of Moscow as saying on August 3 that the door was blown up overnight.
Footage from local station NIKA TV showed the damaged front door and exterior wall, with panes blown out, and chunks of tile around at the entrance.
Nobody was hurt in the explosion.
Reports said the Pension Fund office was operating normally on August 3, with access provided through a side door.
Government-backed legislation that passed in the first of four parliamentary votes on July 19 would raise the retirement age to 63 for women by 2034 and to 65 for men by 2028.
Currently, the retirement age is 55 for women and 60 for men.
The plan sparked widespread anger after it was announced last month, and President Vladimir Putin's approval ratings have fallen.
Tens of thousands of people protested in cities across the country on July 28, and many other demonstrations have been held.
More than 2.9 million people have signed a petition against the reform on change.org.