Egyptian authorities have extended the length of a curfew in Cairo, Alexandria and Suez so it runs from 4:00pm to 8:00am.
The move comes after protesters ignored an army order not to gather in groups and an appeal to observe the curfew.
"The armed forces are appealing to citizens not to stand in groups and to abide by the curfew," state TV reported, adding that violators would be subjected to "legal procedures."
Earlier in the day Egypt's outgoing cabinet met to formally submit its resignation, after President Mubarak told the government to quit. The meeting was headed by Prime Minister Ahmed Nazif.
Thousands of protesters have clashed with police in the northern Egyptian city of Alexandria. Witnesses say the police have used tear gas and live ammunition against the demonstrators demanding an end to President Hosni Mubarak's rule. The death toll in the city since Friday had reached 20.
It is reported that 30 bodies have been taken to Cairo's El Damardash hospital, taking the death toll nationwide to more than 70.
In Cairo, tens of thousands of protesters led by opposition activist Mohamed El Baradei have marched into Tahrir Square.
He has demanded that President Mubarak should step down and set a framework for transition of power as the only way to end street unrests that have rocked Egypt.