Presidential spokesman Yasser Ali said Mursi had appointed Tantawi as his adviser. Mursi also decreed that Abdul-Fatah al-Sessi would replace Tantawi as defense minister and the general commander of the army.

The chief of the army staff, Sami Anan, was appointed as a presidential adviser while Lieutenant-General Sidki Sayed Ahmed was named as Anan’s replacement.

Besides Tantawi and Anan, Morsi also ordered the retirement of the commanders of the navy, air defence and air force.

In an address to the nation on Sunday evening, Mursi said that his move was not directed at individuals.

”The decisions I took today were not meant ever to target certain persons, nor did I intend to embarrass institutions, nor was my aim to narrow freedoms,” he said, Al Jazeera reported.

“I did not mean to send a negative message about anyone, but my aim was the benefit of this nation and its people.

When Hosni Mubarak was ousted in a popular uprising in February 2011 Mubarak transferred authority to the Supreme Council of the Armed Forces, headed by the Tantawi, making him the de facto head of state until elections brought the President Mursi’s Muslim Brotherhood to power this year.

Relations between the military and the Muslim Brotherhood have been tense since the downfall of former President Hosni Mubarak.

The move comes as Egypt’s freshly-elected government faces criticism for unrest in the northern Sinai region, where militants attacked a border post last week, killing 16 troops.