Protesters have broken through a barbed-wire barricade keeping them from the palace of Egyptian President Muhammad Morsi in Cairo.
As many as 10,000 protesters had gathered behind the barrier.
Troops of the Republican Guard, which had ordered rival demonstrators to leave the palace area on December 6, moved to the front gate to secure the main entrance to the palace.
Some demonstrators climbed onto army tanks and waved flags, as hundreds swarmed through and surged up to the walls of the palace after cutting the barbed wire, chanting, "Peaceful, peaceful."
Some kissed the soldiers and police officers.
Tanks were deployed around the palace on December 6, after a night of violence between anti- and pro-Morsi demonstrators. Seven people were killed and hundreds injured in the clashes.
The fresh protest came in response to Morsi's decision to press ahead with a planned referendum on a controversial draft constitution.
Protester Abdel Fattah al-Liwa said the draft, which was rushed through the Islamist-dominated constituant assembly, was proof that the revolution which toppled strongman Hosni Mubarak last year has been stolen.
"No, no, no -- those who understand more than me say that it [the draft constitution] was made under a staircase. This is unacceptable for the constitution of Egypt -- it has been stolen. This revolution has been stolen, by God it has," Liwa said
Morsi offered to discuss the draft but insisted the December 15 referendum would go ahead.
The opposition says the draft fails to protect basic rights and wants the vote suspended.
The standoff sparked days of protests and violent clashes between supporters and opponents of the Islamist president.
UN Human Rights Commissioner Navi Pillay on December 7 said there were some "very worrying" elements in the draft.
Based on reporting by Reuters and AFP