The head of Egypt's state broadcaster, Essam El-Amir, has resigned in protest at how the country has been managed since President Morsi's constitutional declaration and the resulting divisions in society it has caused.
Mohsen El-Shehawy, head of security at the Maspero state broadcasting building, on Thursday said additional presidential guards had been deployed to protect the building.
The state broadcaster is under the supervision of Information Minister Salah Abdel-Maksoud, a member of the Muslim Brotherhood.
Clashes between supporters of President Mohamed Morsi and his opponents which started on Wednesday night have left six dead and 450 injured, according to the health ministry.
Zaghloul El-Balshi, the newly appointed head of the election commission, which is set to organise the constitutional referendum on 15 December, resigned from his post on Wednesday because he refused to monitor "a vote that spilled Egyptian blood."
President Morsi’s aides Seif Abdel-Fattah and Ayman El-Sayyad also resigned on Wednesday.
Police withdrew from the presidential palace on Tuesday when opposition protesters arrived to demonstrate against the president's constitutional declaration and the draft constitution. Supporters of the president attacked an opposition sit-in at the palace on Wednesday. Police returned in attempt to divide the fighting groups.