Egypt's military-led authorities shut down three Islamist-run TV stations on Wednesday including one operated by the Muslim Brotherhood.
The security forces also raided the offices of Al Jazeera's Egyptian news channel and detained at least five of its staff, said Karim El-Assiuti, one of its journalists. Four of them were later released, the channel said.
The New York based press freedom watchdog, Committee to Protect Journalists, said it was "concerned by reports that authorities are shutting down television coverage based on political perspective".
The Muslim Brotherhood tells ITV News they are against violence but will "pay the price of their blood" to restore their ousted president.
Egypt's army has named two further officials in the transitional government as its supporters and opponents vowed to stay on the streets.
There has been outrage in Egypt after 51 people were killed near an barracks where ousted President Mohamed Morsi is thought to be held.