Major group has already warned it would boycott the vote without reconciliation talks.
The stakes for the coming vote are growing, with ominous signs from the military and his rivals on the right.
Tension raises specter of another military intervention like the one that ousted Hosni Mubarak.
Resigned Monday in solidarity with a fellow aide who was fired amid allegations of abuse of office.
Protested against violent anti-government protests; liberal activists staged a smaller demonstration.
Charge came after a government forensic report claimed 28-year-old activist Mohammed el-Gindy was killed in a car accident.
Dozens of youths threw rocks at the Ettihadiya palace after a peaceful march by thousands of demonstrators.
Television screeds by right-wing clerics urging violence against dissenters raise fear of assassinations.Blouin Politics: Morsi moves to protect opposition
Exposed differing views among Muslim and Arab nations on conflict.Blouin Politics: Assad outmaneuvered
Blamed bad hygiene for health problems in rural areas.
