Emergency meetings of the cabinet and parliament have been called in Egypt after a riot at a football match left at least 74 people dead.
State television says the ruling military council has ordered an investigation into the violence in Port Said.
Supporters invaded the pitch following a match between top clubs - and bitter rivals - al-Masry and al-Ahly on Thursday.
Authorities have also declared three days of national mourning.
Protest marches are being planned against the police's inability to contain the violence.
Live television footage showed al-Ahly players being chased by fans after the final whistle of a match won by al-Masry 3-1. Home fans then invaded the pitch to attack the visiting supporters and missiles and flares were thrown.
Some of the dead were security officers.
Doctors say some of the deaths were the result of stab wounds, others were killed in a crush to leave the stadium. Ambulances had trouble getting access through the chaos.
The BBC reports there are fears that the toll could rise. Their correspondent in Cairo says it appears some fans had taken knives into the stadium and the lack of the usual level of security in the stadium might have contributed to the clashes.
Soon after reports of the pitch invasion spread, Egyptian television also showed images of a fire in a soccer stadium in Cairo, after the referee cancelled a match between Zamalek and Ismaili.
The BBC says Egyptian fans are notoriously violent, particularly supporters of al-Ahly, known as Ultras. They were heavily implicated in confrontations during recent political protests.
Meanwhile, the Muslim Brotherhood has blamed supporters of former President Hosni Mubarak for the violence.