A crowd of more than 100 skinheads attacked visitors and police at the Tornado rock festival in the Urals city of Miass, Russian media reported on Monday, RIA Novosti reported.
At least 10 people were injured and a 14-year-old girl died of numerous stab wounds, the local news portal, Chelnovosti.ru reported, citing an unnamed police source. The information is yet to be officially confirmed.
Other sources said some 20 people received various injuries. A dozen of ambulances is currently working at the scene. Media reports about the number of injured vary with some putting the number of injured at more than 100.
According to local media reports, shooting was also heard as a crowd of angry bare-chested skinheads, armed with batons, sticks and iron rods, forced their way through security cordons.
"Police and security guards were either inactive or ran away. Some attackers snatched truncheons from police officers and started beating the visitors," the Chelnovosti reported citing eyewitnesses.
Photos made by the portal's correspondent at the event show police standing aside while people are being beaten up.
Local police spokesmen were not immediately available for a comment.
The festival continues while the area has been cordoned off by the police.
The Ekho Moskvy radio station reported that some 15 attackers were detained, but the majority of the attackers fled.
"Political struggle is seen as the most likely cause of the attack at the Tornado rock festival. The event's main organizer, Valikhan Turgumbayev is going to run in the October legislative polls," an unnamed police source said.
The uralpolit.ru news portal said the attack was coordinated and most likely planned beforehand.
"They [attackers] appeared in an organized manner, they left in an organized manner," the portal quoted Miass governor Igor Voinov as saying.
At least 3,000 people attended the annual rock festival, featuring Russia's most popular rock bands.