Egyptians put their trust in the army, hoping troops would restore order to streets seized by rampaging gangs, but would not open fire to keep Mubarak in power.
In five days of unprecedented protests which have rocked the Arab world, more than 100 people have been killed, investors have taken fright, Mubarak has offered a first glimpse of a plan to step down and 80 million long-suffering Egyptians are caught between hope for democratic reform and fear of chaos.
The United States and European powers were busy tearing up their Middle East policies, which have supported Mubarak at the head of the most populous Arab country for 30 years, turning a blind eye to police brutality and corruption in return for a solid bulwark against first communism and now militant Islam.
The biggest immediate fear was of looting as all public order broke down. Mobs stormed into supermarkets, banks, jewellery shops and government buildings. Thieves at the Egyptian Museum damaged two mummies from the time of the pharaohs.
Through the night, ordinary Egyptians took to the streets armed with clubs, chains and knives to guard neighbourhoods from marauders. By morning, streets were largely deserted, with tanks and armoured vehicles deployed at banks and major buildings.
On a main street in the Maadi district, groups of men stayed up through the night at barricades built from old lampposts, bits of wood and anything else they could find.
The police who had battled protesters for days had disappeared from the streets, replaced by army troops who have so far mostly been embraced by the public.
In surreal scenes, soldiers from Mubarak's army stood by tanks covered in anti-Mubarak graffiti: "Down with Mubarak. Down with the despot. Down with the traitor. Pharaoh out of Egypt. Enough."
Asked how they could let protesters write anti-Mubarak slogans on their vehicles, one soldier said: "These are written by the people, it's the views of the people."
Residents expressed hope the troops would restore order. "People are terrified from these outlaws on the streets looting, attacking and destroying," said Salah Khalife, an employee at a sugar company.
On Saturday, 82-year-old Mubarak bowed to protesters and appointed a vice-president for the first time, a move seen as lining up Omar Suleiman, hitherto his chief of intelligence, as an eventual successor, at least for a transition. Many saw it as ending his son Gamal's long-surmised ambitions to take over.
Egyptians say the changes mean nothing unless Mubarak goes.
"All these changes he made are sedatives," said Khalife. "People don't want Mubarak any more. People want change ... He doesn't want to leave. He is a thug."
In Washington, State Department spokesman P.J. Crowley said on Saturday: "The Egyptian government can't reshuffle the deck and then stand pat."
Since protesters toppled Tunisia's leader two weeks ago, demonstrations have spread across north Africa and the Middle East in an unprecedented wave of anger at authoritarian leaders, many of them entrenched for decades and enjoying U.S. support.
"This is the Arab world's Berlin moment," said Fawaz Gerges of the London School of Economics, comparing the events to the fall of the Berlin Wall in 1989. "The authoritarian wall has fallen, and that's regardless of whether Mubarak survives."
As in Tunisia, Egypt's exploding young population, most of them underemployed and frustrated by oppression at the hands of a corrupt and rapacious elite, were demanding a full clear-out of the old guard, not just a reshuffle of the governing class.
DEATH TOLL OVER 100
Saturday saw the worst bloodshed so far of the five-day uprising. Police shot dead 17 people in Bani Suef, south of Cairo. Various estimates put the overall death toll at more than 100 in the five days of unrest.
Overnight on the Corniche promenade alongside the River Nile, people stayed out after the curfew, standing by tanks and chatting with soldiers who took no action to disperse them.
At one point, dozens of people approached a military cordon carrying a sign reading "Army and People Together". Soldiers pulled back and let the group through: "There is a curfew," one lieutenant said. "But the army isn't going to shoot anyone."
Rosemary Hollis, Middle East expert at London's City University, said the army had to decide whether it stood with Mubarak or the people. "It's one of those moments where, as with the fall of communism in Eastern Europe, they can come down to individual lieutenants and soldiers to decide whether they fire on the crowd or not."
Like other Arab leaders, Mubarak portrays himself as a bulwark against the West's Islamist enemies. Egypt's banned opposition movement the Muslim Brotherhood has been only a small part of the week's events and lays claim to moderation.
"A new era of freedom and democracy is dawning in the Middle East," Kamel El-Helbawy, a cleric from the Brotherhood said from exile in London. "Islamists would not be able to rule Egypt alone. We should and would cooperate."
Sunday is normally a working day in Egypt but banks and financial markets were ordered shut by the central bank.
The stock market's benchmark index had tumbled 16 percent in two days before shutting on Thursday for the weekend.