At least 40 people have been killed in clashes after a football game in the Egyptian city of Port Said, a hospital source tells Al Jazeera.
Scores of others were injured in Wednesday's violence, including players and security personnel.
Fans of the winning al-Masry team flooded the field seconds after the match with al-Ahly, Egypt's top team, was over.
A security official said the fans chased the players and cornered their supporters on the field and around the stadium,
throwing stones and bottles at them.
Most of the victims reportedly died from suffocation or head injuries.
Al-Ahly football players were trapped in the changing room along with supporters.
The team's supporters, Ultras, said on their website that they were heading to Port Said later in the evening.
Al-Masry team won a rare 3-1 against Al-Ahly.
The two teams have a long history of bad blood, and clashes have erupted in recent years between their fans.
