Morsi left Wednesday to visit with authorities in Riyadh, marking his first official diplomatic visit since taking office last month.
Abdul Aziz al-Husseini, a secretary in the nationalist Karama Party, described the visit as a logical step for Egypt's new president. Saudi Arabia, he said, is "one of the most influential countries in the Middle East due to its religious foundations and its economic strength," Egyptian news agency al-Ahram reports.
A constitutional court shot down a measure by Morsi to reinstate the national Parliament. The assembly met briefly Tuesday despite a court decision ruling parliamentary elections were unconstitutional.
Thousands gathered in downtown Cairo to protest the court's ruling. Arab broadcaster al-Jazeera reports that presidential lawyers described the ruling as "null and void."
There is no constitution that defines Morsi's presidential authority. He became the first democratically elected president in Egyptian history and the first since a popular revolution unseated longtime President Hosni Mubarak last year.
U.S. Secretary of State Hillary Clinton is expected in Cairo during the weekend.