CAIRO — President Hosni Mubarak of Egypt struggled to maintain a tenuous hold on power on Saturday as the police withdrew from the major cities and the military did nothing to hold back tens of thousands of demonstrators defying a curfew to call for an end to his nearly 30 years of authoritarian rule. As street protests flared for a fifth day, Mr. Mubarak fired his cabinet and appointed Omar Suleiman, his right-hand man and the country’s intelligence chief, as vice president. Mr. Mubarak, who was vice president himself when he took power after the assassination of President Anwar el-Sadat, had until now steadfastly refused pressure to name any successor, so the move stirred speculation that he was planning to resign. That, in turn, raised the prospect of an unpredictable handover of power in a country that is a pivotal American ally — a fear that administration officials say factored into President Obama’s calculus not to push for Mr. Mubarak’s resignation, at least for now. The appointments of two former generals — Mr. Suleiman and Ahmed Shafik, who was named prime minister — also signaled the central role the armed forces will play in shaping the outcome of the unrest. But even though the military is widely popular with the public, there was no sign that the government shakeup would placate protesters, who added anti-Suleiman slogans to their demands.
On Saturday, Mohamed ElBaradei, the Noble laureate and a leading critic of the government, told Al Jazeera that Mr. Mubarak should step down immediately so that a new “national unity government” could take over, though he offered no details about its makeup. Control of the streets, meanwhile, cycled through a dizzying succession of stages.
After an all-out war against hundreds of thousands of protesters who flooded the streets on Friday night, the legions of black-clad security police officers — a reviled paramilitary force focused on upholding the state — withdrew from the biggest cities.
Looters smashed store windows and ravaged shopping malls as police stations and the national party headquarters burned through the night. Two mummies were destroyed in Cairo’s Egyptian Museum, the country’s chief antiquities official said. Then thousands of army troops stepped in late Friday to reinforce the police. By Saturday morning, a sense of celebration took over the central squares of the capital as at least some members of the military encouraged the protesters instead of cracking down on them.
It was unclear whether the soldiers in the streets were operating without orders or in defiance of them. But their displays of support for the protesters were conspicuous throughout the capital. In the most striking example, four armored military vehicles moved at the front of a crowd of thousands of protesters in a pitched battle against the Egyptian security police defending the Interior Ministry.
But the soldiers refused protesters’ pleas to open fire on the security police. And the police battered the protesters with tear gas, shotguns and rubber bullets. There were pools of blood in the streets, and protesters carried at least a dozen wounded from the front line of the clashes.
Everywhere in Cairo, soldiers and protesters hugged or snapped pictures together on top of military tanks. With the soldiers’ consent, protesters scrawled graffiti denouncing Mr. Mubarak on many of the tanks. “This is the revolution of all the people,” read a common slogan. “No, no, Mubarak” was another.
One camouflage-clad soldier shouted through a megaphone from the top of a tank: “I don’t care what happens, but you are the ones who are going to make the change!”
By Saturday night, informal brigades of mostly young men armed with bats, kitchen knives and other makeshift weapons had taken control, setting up checkpoints around the city.
Some speculated that the sudden withdrawal of the police from the cities — even some museums and embassies in Cairo were left unguarded — was intended to create chaos that could justify a crackdown. And reports of widespread looting and violence did return late Saturday night, dominating the state-controlled news media.
“How come there is no security at all?” asked Mohamed Salmawy, president of the Egyptian Writers Union. “It is very fishy that the police had decided to leave the country completely to the thugs and angry mobs.”
The Mubarak government may have considered its security police more reliable than the military, where service is compulsory for all Egyptian men. While soldiers occupied central squares, a heavy deployment of security police officers remained guarding several closed-off blocks around Mr. Mubarak’s presidential palace.
Before the street fights late Saturday, government officials had acknowledged more than 70 deaths in the unrest, with 40 around Cairo. But the final death toll is likely to be much higher. One doctor in a crowd of protesters said the staff at his Cairo hospital alone had seen 23 people dead from bullet wounds, and he showed digital photographs of the victims.
There were ominous signs of lawlessness Saturday in places where the police had abandoned their posts.
In the northern port city of Alexandria, some residents were unnerved by the young men on patrol.
“We’re Egyptians. We’re real men,” said a shopkeeper, brandishing a machete. “We can protect ourselves.”
Peter Bouckaert, emergencies director of Human Rights Watch, said that he observed a group of soldiers completely surrounded by people asking for help in protecting their neighborhoods. The army told them that they would have to take care of their own neighborhoods and that there might be reinforcements Sunday. “Egypt has been a police state for 30 years. For the police to suddenly disappear from the streets is a shocking experience,” Mr. Bouckaert said.
State television also announced the arrest of an unspecified number of members of the Muslim Brotherhood, the outlawed Islamist group long considered the largest and best organized political group in Egypt, for “acts of theft and terrorism.”
It was unclear, however, what role the Brotherhood played in the protests or might play if Mr. Mubarak were toppled. There have been many signs of Brotherhood members marching and chanting in the crowds. But the throngs —mostly spontaneous — were so large that the Brotherhood’s members seemed far from dominant. Questions about the Brotherhood elicited shouting matches among protesters, with some embracing it and others against it.
If Mr. Mubarak’s decision to pick a vice president aroused hopes of his exit, his choice of Mr. Suleiman did nothing to appease the crowds in the streets. Long trusted with most sensitive matters like the Israeli-Palestinian talks, Mr. Suleiman is well connected in both Washington and Tel Aviv. But he is also Mr. Mubarak’s closest aide, considered almost an alter ego, and the protesters’ negative reaction was immediate.
“Oh Mubarak, oh Suleiman, we have heard that before,” they chanted. “Neither Mubarak nor Suleiman — both are stooges of the Americans.”
Many of the protesters were critical of the United States and complained about American government support for Mr. Mubarak or expressed disappointment with President Obama. But either because of Mr. Obama’s Muslim family history or because of his much-publicized speech here at the start of his presidency, many of the protesters expressed their criticism by telling American journalists that they had something to tell the president, directly.
“I want to send a message to President Obama,” said Mohamed el-Mesry, a middle-aged professional. “I call on President Obama, at least in his statements, to be in solidarity with the Egyptian people and freedom, truly like he says.”
The unrest continued in other areas of Egypt and reverberated across the broader region, where other autocratic leaders have long held on to power.
In Sinai, officials said that the security police had withdrawn from broad portions of the territory, leaving armed Bedouins in control. At least five members of the police, both law enforcement and state security, were killed, officials said.
King Abdullah of Saudi Arabia blamed unnamed agitators for the demonstrations in Egypt. The Saudi Press Agency quoted him saying: “No Arab or Muslim can tolerate any meddling in the security and stability of Arab and Muslim Egypt by those who infiltrated the people in the name of freedom of expression, exploiting it to inject their destructive hatred.” And in Yemen, dozens of protesters took to the streets of Sana in solidarity with Egyptian demonstrators, local media reported. There were large antigovernment demonstrations in Yemen last week, as critics were inspired by the protests that forced the downfall of Tunisia’s president.
The Egyptian government restored cellphone connections, turned off Friday morning in an apparent effort to thwart protesters’ coordination. But Internet access remained shut off Saturday.
The army moved to secure Cairo International Airport on Saturday. The Associated Press reported that as many as 2,000 people had flocked there in a frantic attempt to leave the country. Flights were available, but often rescheduled or canceled later in the day.
As night fell, bursts of gunfire could be heard throughout the city and the suburbs. And the groups of armed young men stopped cars at checkpoints every few blocks throughout the city. Several were visibly coordinating with military officers, even setting up joint military-civilian checkpoints.
One group on the Nile island of Zamalek was ripping up sheets to make armbands that they said soldiers had instructed them to wear. A group at the base of a central bridge kept a case of beer nearby to cheer themselves. And many swelled with pride at their role defending their communities and, they said, their country.
“Who controls the street controls the country,” said Dr. Khaled Abdelfattah, 38, patrolling downtown. “We are in charge now.”
Kareem Fahim, Mona El-Naggar, Scott Nelson and Anthony Shadid contributed reporting from Cairo; Souad Mekhennet and Nicholas Kulish from Alexandria; and J. David Goodman from New York.