CAIRO – Egypt postponed early voting on a contentious draft constitution, and aides to President Mohammed Morsi floated the possibility of canceling the whole referendum in the first signs Friday that the Islamic leader is finally yielding to days of protests and deadly street clashes.

Tens of thousands marched on the presidential palace after pushing past barbed wire fences installed by the army and calling for Morsi to step down. Thousands also camped out in Tahrir Square, birthplace of the uprising that toppled Hosni Mubarak in 2011.

A spokesman for Morsi’s Muslim Brotherhood urged the group’s supporters to practice “self-restraint” after hundreds gathered in front of a mosque near the presidential palace. He appealed for them not to march to the palace and to avoid confrontation.