CAIRO — Representatives from across Egypt’s political spectrum held a rare meeting Thursday to denounce violence, hours before a fresh call for a new wave of mass protests across the country aimed at pressuring President Mohammed Morsi, an Islamist, to accept opposition demands to form a national government and amend the constitution.

Hosted by Egypt’s premier Islamic institution, Al-Azhar, the country’s two rival factions of Islamists and secular-leaning opposition grouping The National Salvation Front pledged to work to halt violence. The meeting followed a week of political rioting that exploded across the nation and left as many as 60 people dead.