The protesters blame the police for failing to prevent a melee after a soccer match in the Mediterranean city of Port Said on Wednesday that killed 74 people in the soccer world's worst violence in 15 years. Tensions across the nation have spiked in the wake of the riot, fueling anger at the ruling generals who took power after the uprising that ousted President Hosni Mubarak last February.
Egyptians furious over the bloodshed took to the streets Friday in Cairo, Alexandria, Suez and several Nile Delta cities, in many cases sparking clashes with security forces.
In the capital, protesters wearing helmets and gas masks fought their way through streets thick with smoke from tear gas toward the Interior Ministry, a frequent target for demonstrations because it is responsible for the police. As night fell, a government building across the street from the Interior Ministry caught fire, sending black smoke billowing into the sky.
In response to the crisis, the ruling military council issued a statement late Friday saying the country is passing through "the most dangerous and most important phase in Egypt's history," and calling on Egyptians to unite in the face of discord.
Prime Minister Kamal el-Ganzouri urged Egypt's intellectuals to intervene to stop the violence and said on the Cabinet's Facebook page that he feared the protesters want to storm the Interior Ministry.
Neither appeal appeared likely to gain much traction with protesters on the streets, many of whom have suggested the authorities either instigated the Port Said violence or intentionally allowed it to happen to retaliate against the soccer fans known as Ultras who played a key role in clashes with security forces during the uprising that toppled Mubarak.
"I came down because what happened in Port Said was a political plan from the military to say it's either them or chaos," said 19-year-old Islam Muharram.
The clashes in Cairo began late Thursday and escalated overnight, with protesters pushing through the barricades erected around the fortress-like building and bringing down a wall of concrete blocks erected outside the ministry two months ago, after similar violence left more than 40 protesters dead.
Ambulances and volunteers on motorcycles ferried the injured, most of them suffering respiratory problems from the tear gas, to field hospitals set up nearby on Tahrir Square.
On the square Friday, thousands of people rallied to condemn the security forces for failing to stop the Port Said bloodshed, and pointed to the incident to bolster their claims that the military has mismanaged Egypt's transition to a democracy. They also called for early presidential elections and demanded the army speed up the transfer of power to a civilian administration.
Meanwhile, some 1,500 protesters marched to the Defense Ministry, chanting "the people want to execute the marshal," referring to Field Marshal Hussein Tantawi, the head of the ruling military council.
The death toll from Friday's violence stood at five.
One security officer was killed and 138 injured, according to the official MENA news agency.
One protester in Cairo was killed after being hit by birdshot at close range, a volunteer doctor said on condition of anonymity because he feared reprisals.
Three protesters also died in Suez after police opened fire on a crowd of about 3,000 people demonstrating in front of the local police headquarters, said health official Mohammed Lasheen. A third protester in Suez was in critical condition with a wound to the neck.
The chief of security in Suez denied the deaths there were from police gunfire.
In Alexandria, thousands of people, some of them carrying photos of those killed in the soccer riot, protested in front of the city's military headquarters, while in Port Said, hundreds rallied in the streets to condemn the attacks on the soccer fans. Some of the demonstrators held banners that read: "Port Said is innocent, this is a cheap conspiracy."
Many in the public and in the newly elected parliament, which held an emergency session Thursday to discuss the violence, blamed the new leadership for letting the soccer riot happen -- whether due to a lack of control by the security forces, or as some allege, intentionally.
The violence in Port Said began after home team Al-Masry pulled off a 3-1 upset win over Cairo's Al-Ahly, Egypt's most powerful club. Al-Masry fans stormed the field, rushing past lines of police to attack Al-Ahly fans.
Survivors described a nightmarish scene in the stadium. Police stood by doing nothing, they said, as Al-Masry fans attacked Al-Ahly supporters, stabbing them and throwing them off bleachers. The parliament later accused the interior minister of "negligence."
Youssef, an 18-year old Al-Ahly supporter who was being treated Friday by the field doctor in Cairo for birdshot in his back and arms, said he had been throwing rocks at the police when he was injured.
"What can I do? I am here to get justice for my beloved brothers who died. I will either get it or I'd rather die like them," said Youssef, who would not give his second name because he said he feared for his life.