Some auto and motorcycle enthusiasts at the Criminal Cursing event clashed with police in Espoo late Saturday night, reported the Finnish language evening daily Iltasanomat.
Some of the spectators attacked police vans at Vermo race track and ripped off their number plates.
The police detained two people on suspicion of causing damage to property and insubordination.
The Western Uusimaa Police Department said it was unlikely that the organisers of the event had the necessary permits.
