The clashes took place between security forces and family members of 21 convicts who were sentenced to death over the Port Said massacre of last February, Xinhua reported.
After the Port Said criminal court Saturday awarded death sentence to 21 accused for last February's massacre of more than 70 people, families of the convicts attempted to break into the prison where they are detained.
Security forces responded by firing tear gas cans to disperse the angry crowd, the state TV reported.
Seventy-three people, including nine top security officials, were arrested after tragic riots at Port Said stadium last year following a soccer match between Port Said's al-Masry and Cairo's al-Ahly teams.
"The final verdict for the rest 52 of them will be announced March 9," said Sobhy Abdel-Meguid, presiding judge of Port Said criminal court, which was held in Cairo for security reasons.