(CBS/AP)-- Tens of thousands of Egyptian protesters pushed past barbed wire fences installed by the army and marched on the presidential palace Friday, calling for President Mohammed Morsi to "leave" a day after they say he offered no concessions to opposition demands.
Climbing over tanks of the Republican Guard, protesters streamed toward the palace as night fell Friday, crossing a no-go zone set up around the compound's perimeter.
The area witnessed deadly clashes on Wednesday, when supporters of Morsi's Muslim Brotherhood group drove out crowds camped outside the palace. The clashes left at least six dead and hundreds injured, deepening the schism between the two sides.
Egypt is plunging deeper into crisis as protesters — mainly liberals — press Morsi to call off a referendum on a draft constitution agreed by his allies.
Rival protests also took place in cities around the country, including in the cities of Alexandria on the Mediterranean coast and Luxor in the south. CBS News correspondent Holly Williams says Egyptian television reported fresh clashes Friday between supporters and opponents of Morsi in front of a mosque in Alexandria, but there were no reports of injuries or serious violence.
Also Friday, the head of Egypt's election committee said the planned voting on the referendum of Egyptians who live abroad had been postponed.
The announcement could signal an attempt by Morsi to give a room for negotiations with the opposition, which is demanding the cancelation of the whole referendum set for a nationwide vote on Dec. 15.
Ismail Hamdi says that the weeklong expatriate voting, which had been due to begin Saturday, will begin Wednesday instead.