CAIRO - Field Marshal Hussein Tantawi, the former head of the military council that ruled Egypt temporarily after its 2011 uprising, has died at the age of 85, Egypt's presidency said on Tuesday, declaring three days of national mourning.

Tantawi - a decorated veteran of wars against Israel in 1956, 1967 and 1973 - was defence minister for 21 years, covering most of the long presidency of Hosni Mubarak.

He led the Supreme Council of the Armed Forces (SCAF) that ruled Egypt for a year-and-a-half after Mubarak was pushed from power in February 2011, the second leader to fall in the Arab Spring protest movement sweeping the region.

Tantawi was too close to Mubarak to be personally popular with protesters who led the uprising in Tahrir Square, though the army's move to appease the demonstrators by deposing Mubarak won some support for the military as an institution.

But while Tantawi sought to give a more down-to-earth image after assuming power, being pictured chatting with passers-by near Tahrir Square, many saw him as a continuity figure seeking to preserve the privileges of the military.

Tantawi was sacked as defence minister in August 2012, a few weeks after the Islamist Mohamed Mursi became president in what was described as the first free and fair elections in Egypt's modern history.

Tantawi then disappeared from view until military chief Abdel Fattah al-Sisi came to power after leading the army to overthrow Mursi in 2013 amid mass protests. Sisi became president a year later.

Tantawi was honoured by Sisi, appearing beside him at various public events. On Tuesday, Sisi mourned Tantawi in a statement and offered condolences to his family.

Tantawi was "a leader and a statesman who took the responsibility of running the country during a very difficult period, during which he wisely and competently confronted the looming dangers that surrounded Egypt", the statement said.

Sisi also defended Tantawi's time in power, which witnessed a series of bloody incidents amid the political turmoil that followed the uprising.

"This man is innocent of any bloodshed... any of the things that took place during this period of conspiracy to bring down the state, I swear to God he is innocent of it," Sisi said in a televised comments.

A major military base in east Cairo would be named after Tantawi, Sisi added. A military funeral ceremony was expected later on Tuesday at a major mosque that also carries his name in Cairo.

(Reporting by Cairo Bureau Writing by Mahmoud Mourad Editing by Catherine Evans and Angus MacSwan)