A video which appears to show a woman being beaten on the head by a Russian police officer is starting to attract attention after it was released on the internet.
The footage was shot in Nizhny Novgorod on Saturday during a protest by activists from the so-called 'Russians' opposition movement.
A policeman is seen hitting a woman on the head with a rubber baton as scuffles break out between police and protesters.
The woman, who was later identified as Yekaterina Zaitseva, falls to the ground after being hit.
Zaitseva is a well-known activist in Nizhny Novgorod who serves as a spokeswoman for her local branch of the Other Russia opposition movement.
Fellow protesters moved her away from the crowd before she was taken to hospital by ambulance.
The Russian Interior Ministry says the policeman has been identified and an investigation is underway.