A Deportivo La Coruna supporter has died following fan clashes before the team's 2-0 defeat at Atletico Madrid on Sunday.
The 43-year-old man, who has not been named, was rescued from the nearby Manzanares River and taken to Madrid's Clinico hospital after being resuscitated. However, hospital sources told Reuters that he had died shortly after 2 p.m. local time.
Isabel Diez, press officer at San Carlos Clinic, told Press Association Sport: "A patient, a male in his 40s, arrived at the hospital with cardiac arrest and suffering from hypothermia. Despite lengthy attempts to resuscitate him, he could not recover from the cardiac arrest and died. We don't know the exact causes as only an autopsy can determine."
Madrid emergency service SAMUR and police said the clash between the rival fans broke out at 9 a.m. near the Vicente Calderon stadium. Eleven other people were injured in the violence, including a police officer who suffered a broken hand.
By Sunday afternoon, police had made 14 arrests.
The Spanish Football Federation (RFEF) strongly condemned the violence and offered its condolences to the family of the man who died.
A statement read: "The RFEF offers its assistance to all those affected by the incidents that have taken place in the vicinity of the Vicente Calderon stadium.
"The RFEF wishes to express its deepest condolences to the family, the fans and the Deportivo La Coruna board, as well as to assist all of them after the death of the fan of their team which happened as a consequence of the serious incidents that took place this morning in the vicinity of the Vicente Calderon stadium and that were carried out by radical groups.
"The RFEF strongly condemns these types of incidents that have nothing to do with football and expresses its complete rejection of violence. The RFEF will continue to work with all its energy and all its means, as it has done so up to now, with the aim of avoiding these lamentable incidents from happening again."
Atletico president Enrique Cerezo said the violence that took place had nothing to do with his club, while coach Diego Simeone said it was society's responsibility to deal with such incidents.
The game kicked off at noon local time and La Liga champions Atletico ran out easy winners, with the goals coming from midfielders Saul Niguez and Arda Turan. After the game, Cerezo told reporters that he wanted to distance his club from the events of the morning.
"We want to say that this has nothing to do with football -- [it was] radical groups which meet and produce such events," Cerezo said. "As president of Atletico I want to make clear that we have nothing to do with these events, at all. We all want peace and agreement between all teams. We know nothing about what happened. The police are investigating. These are radical groups, with nothing to do with sport."
Simeone told his postmatch news conference that he was saddened by what had happened.
"Sincerely, I did not know what had happened [before the game began]," Simeone said. "I was focused on the game. I am not on the phone looking at what has happened in society. This is a social problem, not a football problem. We are very sad about what happened, and condemn it completely. It should not happen again. Those whose job it is to work on this issue will work on it."
The match had kicked off as scheduled, although the Liga de Futbol Profesional soon released a statement saying it had tried without success to stop the game from going ahead due to the incident.
Colchoneros defender Diego Godin told Canal Plus after the final whistle that he and his team had focused on doing their jobs, while those who use football as a pretext for violence.
"We did not know much about what had happened -- sincerely, we were just preparing for the game," Godin said. "We must eradicate this from football. These people do not represent any club or the game. The fans of Atletico and Deportivo cannot pay the price of what a few have done."
Before kick-off, Atletico released a statement to condemn the incident, without going into any specifics on what had occurred.
"We must fight together to end the scourge of violence in sport," the statement read. "Club Atletico de Madrid strongly condemns the incidents that occurred in the area of Madrid Rio in the hours prior to the match. The values promoted by sport must prevail over any rivalry and we must fight together against the scourge of violence."
Information from The Associated Press was used in this report.