A police officer died as trouble flared ahead of Athletic Bilbao’s Europa League clash with Spartak Moscow.
Videos of fireworks and flares being let off were widely shared on social media ahead of the fixture at San Mames, as pre-match calls for calm were ignored.
Further images showed supporters clashing with police, with the local force later reporting the death of an officer.
“Our condolences to colleagues, friends and relatives of the Ertzainza (force officer) who died in an act of service,” Bilbao Police wrote on Twitter. The cause of death was not reported.
Athletic added a statement of their own, saying: “Our heartfelt condolences to the family and friends of the deceased officer today. Athletic Club express their strongest rejection of violence generated around football.”
At his post-match press conference, Athletic head coach Jose Angel Ziganda said, in quotes carried on Twitter: “We didn’t know anything. We found out at the end of the game. I don’t know if would have been better or worse to suspend the match.”
Fears of trouble had existed prior to the game, with more Russians expected to travel than there were tickets. Spartak posted a lengthy call for good behaviour on their official website, reminding supporters that there were no tickets available and that “the cashier’s office will not work”.
The statement went on to ask fans not to “succumb to provocations and not enter conflicts with local residents”. Athletic said that security would be reinforced in anticipation of “the large influx of visiting fans”.
UEFA was contacted for comment.