UEFA has opened an investigation into the crowd trouble which marred Wednesday's Champions League third-qualifying round tie between Dnipro Dnipropetrovsk and FC Copenhagen.
The travelling Copenhagen fans had to seek refuge under the stands after appearing to be attacked by Dnipro supporters at the start of the second half, with the game being delayed by 15 minutes.
UEFA said it "received the report this morning and an investigation has been opened against Dnipro Dnipropetrovsk for crowd disturbance and insufficient organisation".
The return match is scheduled for August 6 and the matter will be decided on August 14 at UEFA's next disciplinary meeting.
Dnipro fans have said they were provoked by a Russian flag being waved by Copenhagen fans, possibly referring to the on-going conflict in eastern Ukraine, between the country and Russia.
This claim has been fiercely denied by the Danish club.