Two members of Pussy Riot were left with chemical burns and head injuries after they were attacked by youths in a branch of McDonald's, the group says.
Maria Alyokhina and Nadezhda Tolokonnikova were left covered in green stains after "an organised group" of young men attacked them with antiseptic, pepper spray and weapons, Tolokonnikova's husband Pyotr Verzilov said in an e-mail.
A video released by Pussy Riot shows six young men wearing patriotic Russian symbols shouting obscenities at the women while videoing the action in a branch of the fast-food chain in the Russian city of Nizhny Novgorod.
One held up a placard saying: "Dirty whores, get out of the city."
Pussy Riot's lawyer Yevgeny Gubin told Interfax that the attackers also "threw metal objects" at the women.
This isn't the first time members of the anti-government protest group have been attacked since they were released from two-year prison sentences for hooliganism in December.
They were whipped by Cossacks and questioned by police over allegations of theft in Sochi during the Winter Olympics, according to a video shot by the group.
Tolokonnikova posted doctors' statements on Twitter saying she suffered chemical burns to her eyes, face and hands from the attack on Thursday.
Alyokhina said she required stitches for scratches on her forehead and suffered concussion.
"At 7.20am, an organised group barged into the McDonald's where members of Pussy Riot with their crew were having breakfast and attacked them with pepper spray, green antiseptic and other weapons," Verzilov said.
Police are investigating the incident, the Interfax news agency reports.
The women were detained in Moscow last week at a protest against the jailing of anti-Putin activists over street clashes in 2012.
