Tens of thousands of people have gathered in Rabaa Al Adawia square to protest against the military intervention.
Protesters are shouting slogans supporting Morsi and carrying Morsi's photos and Egyptian flags.
Tight security measures have been taken to prevent any act of violence during the rally.
Head of Egypt's armed forces Gen. Abdul Fattah al-Sisi had announced on Wednesday the suspension of the constitution and the head of Egypt's Supreme Constitutional Court would be sworn in as the interim President.
Adly Mahmud Mansour was sworn in on Thursday as the interim president.
