Defence Minister General Abdel Fattah al-Sisi has declared Supreme Constitutional Court president Adly Mansour as interim president of Egypt as part of a transitional road map, practically eliminating President Mohamed Morsy from office.

The declaration hopes to conclude a crippling political impasse in Egypt following vast protests against Morsy demanding early presidential elections.

In a televised speech late Wednesday, Sisi said the roadmap includes suspending the current constitution and naming constitutional court head as interim president until a new president is elected at the polls. According to the roadmap, Mansour would be granted the power to issue constitutional declarations. A cross-party panel would be formed to propose amendments to the constitution, it stipulates.

The court would meanwhile be asked to approve a law on parliamentary elections and prepare for parliamentary polls, Sisi said.

The minister also added that a committee will handle national reconciliation and mechanisms will be put in place to ensure Egypt enjoys a free media.

Sisi pointed that the army had been at great pains to contain political tensions and foster national reconciliation since November but that attempts had been rejected by the presidency.

Sisi accused Morsy of failing to meet popular demands in his Tuesday speech.

The statement urged protesters on the streets to remain peaceful, vowing that any breach of the law would be dealt with in conjunction with the police.

The Arab world's most populous nation has been in turmoil since the fall of Mubarak as Arab Spring uprisings took hold in early 2011, arousing concern among allies in the West and in Israel, with which Egypt has a 1979 peace treaty.

The elected Muslim Brotherhood president, in office for just a year, remained out of sight in a Republican Guard barracks surrounded by barbed wire, barriers and troops, but military sources denied media reports that he was under arrest.

"For the sake of Egypt and for historical accuracy, let's call what is happening by its real name: military coup," Mursi's national security adviser Essam El-Haddad said in a statement, warning of "considerable bloodshed" to come.