Egypt has declared a state of emergency and called on its armed forces to take power, state news agency MENA said.
In a statement, the interior ministry said it was called by Interior Minister Ahmed Abu Zeid, who had urged soldiers and security forces to protect Egypt from the military coup that ousted the Islamist president Mohamed Morsi last month.
The announcement came after the military announced it had taken control of the state broadcaster, the national broadcaster, and the interior minister’s office.
It was the first time that Egypt had declared a security emergency.
The decree was made by a cabinet meeting and is a move that is unlikely to be challenged by the court that oversees the judiciary.
The state news service said in a statement that the decree, signed by Prime Minister Adly Mansour, would protect the country’s “national unity, stability, and integrity”.
Egypt has seen some of the worst violence in years and the military has been accused of using torture and mass arrests against protesters and supporters.
The army’s takeover of the judiciary and state media on Saturday saw tens of thousands of people marching through Cairo.
The BBC’s Mohamed Fadel in Cairo says the military’s move to take over the courts and media was seen as a step towards a more authoritarian state.
He says this was a move towards the sort of authoritarianism seen in neighbouring Saudi Arabia and the United Arab Emirates, which are also embroiled in military coups.
The military’s moves to take control of Egypt’s media, a critical component of democracy, came after weeks of protests that have drawn tens of millions of people into the streets demanding more freedoms.
Egyptian President Mohamed Morsi was ousted by the military in July, with the Islamist party calling the ousting unconstitutional.
But many people have been killed in the violence and Morsi was removed from power a year later.