Morsi's aides denounced Saturday's violence and sought to dismiss the notion of a country in chaos.
Ayman Ali, a senior presidential aide, called on the media not to provide a "political cover" to the violence sweeping the country and dismissed as exaggerated claims that the country's police force was in disarray.
Another presidential aide, Bakinam el-Sharqawy, lamented that the focus on protests and violence created an image of instability in Egypt that kept foreign investors away.
In anticipation of more violence, authorities beefed up security near the Interior Ministry, which is in charge of the police force, with riot police deploying in the streets around the complex in central Cairo.
The president of the international soccer governing body FIFA appealed for calm.
"I call on football fans in Egypt to remain peaceful. Violence is never a solution and is contrary to the spirit of sport," Sepp Blatter tweeted.
Earlier at the courthouse across town, Judge Sobhi Abdel-Maguid read out the verdict live on TV, sentencing five defendants to life in prison and nine others to 15 years in jail. Six defendants received 10-year jail terms, two more got five years and a single defendant received a 12-month sentence.
The court's decision on the nine Port Said security officers on trial was among the most highly anticipated — and potentially explosive — verdicts. In the end, the judges sentenced the city's former security chief, Maj. Gen. Essam Samak, and a colonel both to 15 years in prison, while the others were acquitted.
Al-Ahly's fans accuse the police of collusion in the killing of their fellow supporters, arguing that they had advance knowledge of plans by supporters of Port Said's Al-Masry to attack them. They also accuse them of standing by as the Al-Masry fans attacked the visiting Al-Ahly supporters.
The court rulings can be appealed before a higher court.
Many residents of Port Said say the trial is unjust and politicized, and soccer fans in the city have felt that authorities were biased in favor of Al-Ahly, Egypt's most powerful club.
In Port Said, a city that for weeks has been in open rebellion against Morsi, the Islamist leader, several hundred people, many of them relatives of the defendants, gathered outside the local security headquarters to vent their anger. They chanted slogans against Morsi's government and the verdicts. Police pulled out of the city on Friday after days of battling protesters in deadly clashes. The army has taken over security in the city, a move that was warmly welcomed by residents.
Some people in a cafe watching the verdict live on TV hit their heads in frustration, while others broke down and wept. Some said they can live with the verdict because an appeal leaves room for hope.
"There's still an appeal process. God willing, our rights will be restored," said Islam Ezzeddin, a local soccer fan. "We are not thugs. I hope to God when there's an appeal, that we feel we live in a country of law and justice."
However, the national railways chief, Hussein Zakaria, ordered trains headed to Port Said to terminate their services at Ismailiya, another Suez Canal city south of Port Said. He said the measure was taken out of fear for the safety of passengers.
Late on Saturday, activists in the city declared the start of a new general strike, with bands of protesters moving around the city pleading with business owners to shutter down.
Batrawy reported from Port Said.