The Muslim Brotherhood has rejected a transition timetable set out by the military-backed interim president Adly Mansour, as the National Salvation Front, Egypt's main opposition bloc, denounced a decree which invests the new leader with extensive powers.
The rejection from rival groups in Egypt came on Tuesday, as the transitional administration named the Prime Minister as Hazem el-Beblawi and appointed liberal opposition chief and Nobel Peace laureate Mohamed ElBaradei as vice president for foreign relations.
Essam el-Erian, a senior Brotherhood figure and deputy head of its Freedom and Justice Party, the political arm of the Muslim Brotherhood, dismissed the transition timetable on Tuesday, saying it would take Egypt "back to zero".
"The cowards are not sleeping, but Egypt will not surrender," he said.
"The people created their constitution with their votes," el-Eiran wrote on his Facebook page, referring to the constitution that Islamists pushed to finalisation and then was passed in a national referendum during former President Mohamed Morsi's year in office.
Egypt's interim administration published a timetable for a transition to a new democratic government hours after the army shot dead scores of people outside the elite Republican Guards' headquarters in Cairo on Monday.
The plan includes holding parliamentary elections by 2014, after which a date will be announced for a presidential ballot.
The country will have five months to amend the current draft constitution, suspended following Morsi's removal last week, ratify it in a referendum, and then hold parliamentary elections, according to the text of the 33-article decree published online.
The process will take no more than 210 days, according to the decree, meaning elections will be by February at the latest.
"The National Salvation Front announces its rejection of the constitutional decree," the group said in a statement.
The NSF complained of a lack of consultation before the charter was adopted.
"We call for it to be amended and will propose our own amendments to the president," the group added.
Earlier, the grassroots Tamarod campaign, which organised the mass protests that led to Morsi's overthrow, also complained it had not been consulted on the transition plan.
Tamarod spokesman Mahmud Badr said the movement would itself make proposals for changes to the blueprint.
For its part, the US cautiously welcomed the plan.
"We are encouraged the interim government has laid out a plan for the path forward," State Department spokeswoman Jen Psaki told a daily briefing. "The details of a path back to a democratically elected civilian government are for the Egyptian people to decide," she added.
Military issues warning
The Egyptian military on Tuesday issued a statement defending the legitimacy of the interim government,.
Defense Minister Abdel-Fattah el-Sissi warned against anyone who would put "the homeland at the people in jeopardy" and any attempt to disrupt the country's "difficult and complex" transition.
Elsewhere, Egypt's prosecutor general on Tuesday began investigating 650 people suspected of involvement in violence on Monday, although it is not clear who, exactly, is under investigation.
Meanwhile, one of the leading critics of Morsi's government, the United Arab Emirates, has pledged $3bn in loans and grants to Egypt's new government.
The Gulf state alleges that Islamist groups backed by the Muslim Brotherhood have sought to topple its Western-backed ruling system.
Saudi Arabia also approved a $5bn aid package to Egypt, which is to include $2bn in central bank deposits, $2bn in in energy products and $1bn in cash.