EGYPT'S political transition after President Mohamed Mursi's ousting has stumbled at the first hurdle after the choice of liberal politician Mohamed ElBaradei as interim Prime Minister was thrown into doubt by Islamist objections.

Mr Mursi's Muslim Brotherhood movement called for further protests yesterday after dozens of people were killed and more than 1000 wounded on Friday in clashes between his supporters, opponents and the military.

Rival factions fought street battles in central Cairo and many others cities and towns in the Arab world's most populous state, underlining the need for a swift political solution.

The Mediterranean city Alexandria, where 14 people have died, was the scene of some of the worst clashes in the upheaval since Mr Mursi's removal from office.

Mr ElBaradei's nomination had been confirmed by several sources on Saturday, but just before midnight a presidential spokesman said the Prime Minister had not in fact been chosen.

The abrupt U-turn came amid opposition to the appointment by the hardline Alnour Party, Egypt's second Islamist force after the Brotherhood, highlighting the challenge the military faces in finding consensus on who should run the country.

The presidential spokesman said: "We extend our hand to everyone. Everyone is a part of this nation.

"The Muslim Brotherhood has plenty of opportunities to run for all elections, including the coming presidential elections or the ones to follow."

Minutes after he spoke, state media reported the public prosecutor had ordered four Brotherhood leaders to be detained for a further 15 days after being held last week on accusations of inciting violence against protesters.

The Brotherhood has pledged to continue protests until Mr Mursi is reinstated.

The Alnour Party, on the other hand, had agreed to the army-backed transition plan leading to new elections, so its withdrawal from the process would strip the plan of vital Islamist support.

Following the Alnour rejection, the interim administration headed by Adly Mansour delayed naming the new prime minister.

Mr Mursi's removal last week has raised alarm among Egypt's allies in the west, including main aid donors the US, the European Union, and in Israel.

President Barack Obama condemned the violence and said the US was not working with any particular party or group in Egypt.

Washington has not condemned the military takeover or called it a coup, prompting suspicion in the Brotherhood that it tacitly supports the overthrow of the country's first freely elected president.

Mr Obama has ordered a review to determine whether annual US assistance of $1.5 billion, most which goes to the Egyptian military, should be cut off, as required by law if a country's military ousts a democratically elected leader.