Democracy protesters in Cairo fear the army will thwart their revolution by putting up a "new Mubarak" in a presidential election later this year.
Many of the generals who now run Egypt are strongly anti-reformist and are determined to preserve the lucrative privileges they have amassed during decades of authoritarian rule.
There is growing friction between protesters and soldiers, following a honeymoon period after Hosni Mubarak was forced from office.
"The revolution is not finished yet, and we don't want the army to take over here," said Mohamed Foud Gadalla, a professor of international law at Cairo University, to loud cheers, during a victory rally by protesters.
The protesters are suspicious about the commitment of their new military government -- led by Field Marshal Mohamad Tantawi, 76, the conservative head of the Higher Military Council -- to reform a corrupt system from which they have benefited for decades.
The financial interests of serving and retired officers are greatest in the food, petrol, construction and hotel sectors. The military owns land in areas such as the Red Sea whose value has soared due to tourism. Their business empires ensure that officers enjoy luxurious lives and comfortable retirements.
Protesters fear the army will encourage a figure from the old regime to run as president. An army candidate could have a clear run at power. There is little sign of protesters forming political parties for the election in six months. Protesters celebrating in Cairo on Friday accept the army must help preserve order until a transition to civilian rule, but Ahmed Naguib, 33, who helped start the Facebook page which launched the revolution, said: "We went on to the streets on Friday in part to keep the military in check.
"We are going out to show who is behind this victory, and to show what we can do."