Morsy's recalling of parliament is likely to please his backers in the Muslim Brotherhood, which won the largest share of seats in parliament in elections this year.
Dozens of riot police and barriers surrounded the parliamentary building, but guards there allowed lawmakers into the building Monday, Egypt's state-run Nile TV reported.
Morsy took the helm of a deeply divided nation that is economically strapped and lacks a working government. He quickly indicated that Egypt's legislative power would return to civilian hands -- and while praising the generals, he said their job was "to protect the boundaries and security of the country."
Hassan said that as president, Morsy "has the authority to take any decision, regardless if it's right or wrong."
But, he added, "Overturning the constitutional court ruling and reinstating parliament is against the constitution, especially that there is no appeal on such court rulings."