Swiss police have said that Sion fans attacked the team bus of second-tier side Servette as it headed home from an away match.
Police in Aargau canton said on Sunday that the incident -- which left Servette's two drivers injured due to broken glass -- happened at a highway rest area on Saturday evening.
The Servette players were returning home from a match at Wil. As they were about to set off, another bus containing fans of Swiss Super League side Sion arrived.
The Sion supporters attacked the Servette bus, damaging the front and side windows of the vehicle.
Police have said that they arrived at the scene quickly and brought the situation under control.