A police officer has died in Bilbao following violent clashes between rival factions of ultras ahead of Thursday’s Europa League clash.
Local government has since claimed the police officer from the Ertzaintza - the Basque Country's police force - suffered from heart failure.
Video footage showed ongoing street battles between separate sets of fans, with fireworks frequently being launched in the street surrounding Athletic’s San Mames stadium.
The police offer, who was named as 51-year-old Inocencio Alonso Garcia, was one of 500 police officers deployed for the ‘high risk’ match due to the Russian ultras who had travelled for the match.
The Bilbao police paid their respects to the officer on social media later that night: “Our condolences to colleagues, friends and relatives of the Ertzaina who died in active service.”
The police also said many of the travelling Russian contingent had arrived with batons and knives in preparation for the violence.