The nationwide state of emergency, announced by a presidency statement read out on state television, began at 4pm (2pm GMT).
The exceptional measures came as “the security and order of the nation face danger due to deliberate sabotage, and attacks on public and private buildings and the loss of life by extremist groups,” the presidency said.
Interim president Adly Mansour “has tasked the armed forces, in cooperation with the police, to take all necessary measures to maintain security and order and to protect public and private property and the lives of citizens.”
The emergency was imposed come as clashes raged around the country after police moved in to disperse two pro-Morsi camps in Cairo.
At least 124 were killed in the Rabaa al-Adawiya camp alone, according to an AFP count.