The Muslim Brotherhood said it wants nothing to do with a plan by Egypt's interim president to amend the constitution and hold fresh elections.
Senior Brotherhood leader Essam el-Erian issued a statement on his official Facebook page rejecting the proposal, accusing interim President Adly Mansour of usurping legislative power.
The Brotherhood's response comes as thousands of members again took to Rabaa al-Adawiya square in Cairo to call for the reinstatement of ousted President Mohamed Morsi.
Many, like Ashraf Awad, say they will continue protesting until Morsi is reinstated.
"I don't accept the declaration of the constitution yesterday," Ashraf Awad, a supporter of Mohammed Morsi said. "Of course no one voted for this president [interim President Adly Mansour]. He is illegitimate in being sworn in, so all decisions he makes, people will not recognize."
Tensions remain high as the Muslim Brotherhood and the Egyptian military continue to trade blame for Monday's violence that left at least 51 people dead. The Brotherhood says the army opened fire on Morsi supporters without reason. The army says troops shot only after coming under gunfire from terrorists trying to storm a military headquarters in Cairo.
Interim president Mansour has called for restraint and for an independent investigation. His decree on a transition plan, issued late Monday, calls for a referendum to take place within five months to ratify amendments to the country's constitution. Parliamentary elections would take place early next year followed by a new presidential election.
Egypt's army suspended the Islamist-drafted constitution and overthrew Morsi last week, following massive protests against his rule.
The Egyptian Military's Roadmap
Temporary suspension of the constitution
Interim civilian government headed by Adly Mansour
Early presidential and parliamentary elections
Formation of a national reconciliation committee
Implementation of a media code of ethics
The army described the move as necessary to enforce the will of the millions of people who had repeatedly demanded his resignation. The Muslim Brotherhood says the action was a military coup.
White House spokesman Jay Carney said Monday the U.S. is concerned by the increasing violence and what he called a "dangerous level of political polarization" in Egypt. He also said cutting off aid to Egypt would not be in Washington's best interests. Egypt is the second-largest recipient of U.S. financial assistance behind Israel.