Riot police were called in to break up clashes after a group of Twente ultras sought out Hammarby supporters in the main stand after the final whistle in the first leg of the second qualifying round last Thursday, local media reported.

After consultations with the Dutch and Swedish authorities, as well as Hammarby, Twente have also advised their 1,500 supporters with tickets not to gather in large groups or move around the Swedish capital.

A Swedish supporter was taken to hospital after falling from the stands during the clashes, with Hammarby reporting on Friday that the fan was in a stable condition.

Dutch police said on Friday that nine people had been arrested in the aftermath of the clashes at Twente's stadium in Enschede.

The first leg ended with a 1-0 win for the Dutch side.