Spanish police say a riot officer died of cardiac arrest Thursday after clashes in Bilbao between soccer fans before a Europa League match.
Police said the officer died in hospital after clashes outside San Mames Stadium in the Basque Country city of Bilbao in northern Spain, ahead of the game between Athletic Bilbao and Spartak Moscow.
"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 identity of the officer was not immediately disclosed.
Crazy scenes at Athletic Bilbao vs Spartak Moscow tonight 💥💥 pic.twitter.com/Q1OQ7UOSgk— Away Days Videos (@AwayDaysVideos) February 22, 2018
Police were escorting some Spartak fans into the stadium, but a stray group allegedly started igniting fireworks and throwing flares and objects toward Athletic supporters and police officers.
The fighting spread onto the streets near the stadium and police struggled to restore order. Many fans were seen trying to run away from the trouble as fireworks exploded all around.
Police said a Russian man was injured, but the extent of his injuries was not immediately disclosed. Five people were arrested -- three Russian nationals and two Spaniards.
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."
The game went on despite the violence, with Spartak winning the second leg 2-1, but Athletic Bilbao advancing to the round of 16, 4-3 on aggregate.
At his postmatch news conference, Athletic coach Jose Angel Ziganda said: "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."
In a statement, UEFA said it "strongly condemns the violent clashes which occurred in Bilbao. We are in contact with local authorities to obtain further information on these incidents.''
La Liga said it "deplores and condemns the death" of the police officer, and its president said he hopes FIFA and UEFA take action to halt fan violence.
"The Russian ultras shouldn't have travelled to Bilbao because of their history," Javier Tebas told AS.
Most recently, UEFA fined Spartak €3,000 in December for setting off fireworks at a Champions League game a month earlier. In September, they were fined €60,000 for fireworks -- including one aimed at a referee -- and banned from selling tickets to their next European away match.
UEFA charged the club in December after youth player Leonid Mironov was acccused of racially abusing Liverpool's Rhian Brewster at a game in England. They were fined €33,000 and ordered to close part of their stadium after fans directed monkey chants at Liverpool players in Moscow in September.
Spartak were also condemned by FIFA and anti-racism groups last month after a player took over the club's Twitter feed and posted a video describing his own black teammates as "chocolates melting in the sun."
Six years ago, a fan died in Bilbao in clashes after a match between Athletic and German club Schalke.
Information from The Associated Press and Press Association was used in this report.