Police have released five youths detained after trouble broke out at the end of a concert in Helsinki's Kaivopuisto park on Sunday.
The detained were between the ages of 15 and 18. They were fined for insubordination and vandalism.
Four other youths under 15 years old were sent home earlier. The free concert drew a crowd of 50,000 people, attracted by Finnish pop acts such as Anna Abreu, Jenni Vartiainen, Mariko, Negative and Poets of the Fall.
About 150 participants started throwing bottles and causing a disturbance and clashed with police after the concert around 7 pm.
Scores of police officers were summoned to the scene to restore order. At least three police cars were damaged in the mêlée. No one was reported injured during the incident.
City officials say a permit will probably not be issued next year for such an event because of the condition in which the park was left.
The concert was staged as part of celebrations in the run-up to Helsinki Day on Thursday, June 12.