Tarek Abbas, a 54-year-old engineer, said reconvening Parliament was in the country’s best interest. “Now the lawmakers can monitor the SCAF-appointed government and the president himself,” he said.

Momen Zaarour, a lawmaker from the Muslim Brotherhood’s political wing, the Freedom and Justice Party, said he attended the session to support Morsi’s decree.

“We respect the judiciary’s rulings and the constitutional court’s ruling,” Zaarour said. He added that the Parliament’s constitutional committee was studying the court’s decision, indicating that lawmakers wouldn’t bow to the ruling and that the standoff would continue.

For the second day in a row, Morsi appeared publicly in a military graduation ceremony seated between Tantawi and Sami Anan, the military chief of staff, despite the rising tensions.

The elections, which were supposed to bring stability and democratic governance, have instead created even more uncertainty. Katatni said he’d appeal the court’s ruling June 14 that led to the dissolution of the Parliament’s lower house on the grounds that seats had been contested in violation of election laws.

On Monday, the court issued a sharp statement rejecting Morsi’s decree, saying that “All the rulings and decisions of the Supreme Constitutional Court are final and not subject to appeal . . . and are binding for all state institutions.”

Speaking on June 30, after his inauguration, Morsi hinted at his discontent over Parliament’s dissolution, saying that the military council “has fulfilled their promise that they will never be a substitute for the people’s will” and pledged that “the armed forces will go back to the barracks.”

Special correspondent Hassan el Naggar contributed to this article.