Information Minister Salah Abdel-Maksoud also said the National Defense Council would consider implementing a curfew and a state of emergency as violence persisted in Cairo, Port Said, and Suez.
All of those killed in Port Said on Saturday died of gunshot wounds, as protesters angered by the court verdict battled police outside the prison where the defendants were being held and at police stations, said Abdel Rahman Farah, the manager of the city's hospitals. Two soccer players were among the dead, the Associated Press reported.
In Saturday's verdict, a Cairo judge sentenced to death 21 people charged in the killing of 74 soccer fans in a riot that broke out between fans of the club team al-Ahly and Port Said's al-Masry club team after a match in the coastal city in February last year. A verdict is expected for the remaining 52 defendants in March.
The announcement sparked exclamations of surprise and tears from victims' families in the courtroom and outside the al-Ahly soccer club in Cairo where fans had gathered. But it sparked anger in Port Said, home to most of the defendants, where their families and supporters tried to storm the prison.
Television news footage showed protesters fighting police amid clouds of tear gas outside the prison complex and along side streets on Saturday afternoon.
"All the shops are closed, and the city is under complete paralysis," said Mohamed, a hotel owner in the center of the city who declined to give his last name out of anxiety about the security situation.
Others reported that residents were stocking up on groceries in preparation for days of clashes.
In the two years since a popular uprising ousted former president Hosni Mubarak, Egyptians spanning the spectrum from rights groups and victims of violence and corruption to defendants and their supporters have complained of a highly politicized and ineffective justice system. Many say the courts have failed to adequately investigate charges and that verdicts are often issued less as the culmination of a comprehensive trial than as token gestures to appease popular anger.
"It was a political ruling and nothing more," said Mohamed Zakaria, a representative of the Port Said teacher's union. "They want to minimize the protests in Tahrir and get the Ultras on the side of the ruling authorities."