CAIRO - Egypt's Islamist President-elect Mohamed Mursi will give a speech to crowds in Tahrir Square on Friday but his party appears to have lost in a power struggle with the ruling military council over where he will take his oath of office.Details about the historic swearing-in ceremony were announced in a late statement from the presidency on Thursday which stated that Mursi will take the oath of office in front of the Supreme Constitutional Court on Saturday at 11 a.m. Cairo time.Following the meetings, a presidential spokesman issued a statement that mentioned only Mursi's plans to address the nation on Friday from Tahrir Square where hundreds of protesters have been camped out for weeks to press the military council to swiftly transfer all powers to civilian rulers.Later, a senior judge in the Supreme Constitutional Court told the state news agency MENA that Mursi would take the oath in front of a panel of Judges from the Supreme Constitutional Court on Saturday.The army council that has ruled Egypt since pushing former President Hosni Mubarak aside to calm a popular uprising last year has promised to hand back control by July 1.Yet the military has demonstrated that it intends to keep its hands firmly on the real levers of power.Field Marshal Hussein Tantawi, 76, who served as Mubarak's defence minister for two decades, will keep that post in Mursi's future cabinet, an army council member said on Wednesday night."The government will have a defence minister who is head of the Supreme Council of the Armed Forces," Major-General Mohamed Assar said on private CBC television.Asked by the talk show host if this meant Tantawi would keep his defence portfolio, Assar said: "Exactly. What is wrong with that? He is the head of the SCAF, the defence minister and the commander of the armed forces."The military council led by Tantawi has managed a turbulent and sometimes violent transition period in which Egypt's first free parliamentary and presidential elections have taken place.Assar's assertion that Tantawi would remain in place even before Mursi has been sworn in on Saturday illustrates the limits the military seeks to set on his presidential authority.After being sworn-in as the first freely elected civilian president of the biggest Arab state, Mursi will attend a celebration in Cairo University where he will give a speech, according to the presidency statement.The Muslim Brotherhood had wanted Mursi sworn-in before parliament, in line with past practice, but an army-backed court dissolved the Islamist-dominated lower house earlier this month.The generals said the same court should hear Mursi take his oath of office.Mursi held talks about the oath-taking on Thursday with the Muslim Brotherhood's general guide Mohamed Badie and prominent public and legal figures and politicians at the presidential palace.