Egyptian President Mohamed Morsi has driven back the biggest challenge to civilian rule by dismissing top generals and tearing up their legal attempt to curb his power in a bold bid to end 60 years of military leadership.

Taking the country by surprise, Morsi pushed Field Marshal Hussein Tantawi into retirement on Sunday after heading the military forces for two decades.

He is replaced by Colonel General Abdel-Fatah el-Sissi.

El-Sissi, one of the youngest members of the Supreme Council of the Armed Forces (SCAF), has been the director of military intelligence since SCAF took power in February 2011, after the fall of President Hosni Mubarak.

The 57-year-old newly appointed defence minister was at the forefront of the drive to sideline former spy-chief and staunch Mubarak ally, the late Omar Suleiman.

Sidqi Sobhi Sayed replaced Sami Anan as chief of staff 

El-Sissi caused major embarrassment for SCAF in March last year when came out with a press statement in which he admitted that Egyptian soldiers conducted "virginity tests" for female demonstrators in Tahrir Square during the revolution.

He defended the use of the tests, saying they were necessary to absolve soldiers of accusations of rape.

El-Sissi is believed to have close ties to the Muslim Brotherhood, but denies that he is a member of the Islamist group.

As well as ordering the retirement of Tantawi, Morsi also ended the career of Sami Anan as chief of staff.

Anan was replaced with Sidqi Sobhi Sayed, a 56-year-old general with good relations with tribes in the Sinai where there has been unrest in recent days.

Sobhi led the Third Field Army based in Suez, on the border with Sinai.

Judge Mahmoud Mekki was appointed as vice-president 

Egypt's official news agency quoted an unnamed military official late on Sunday as saying there had been no "negative reaction" from within the military - and a day after the orders, no unusual army movements had been detected anywhere across the nation.

Morsi also appointed senior judge Mahmoud Mekki as his vice-president.

Mekki, who graduated from police college and worked as a police officer in Central Security Forces, was part of the independent judges movement during the Mubarak-era that pushed for more judicial independence.

He is alleged to have rejected an offer made by the Muslim Brotherhood to be their presidential candidate in the 2012 presidential elections.

Source: Al Jazeera and agencies