Egyptian President Hosni Mubarak's ruling apparatus has relied on the military since he came to power in 1981.
All four Egyptian presidents since the 1950's have come from the military, now led by Field Marshal Mohamed Hussein Tantawi.
The army now guards key installations after police lost control of the streets, but it has neglected to enforce the curfew and has often fraternized with protesters rather than confront them.
Here are some details of Egypt's military which totals around 468,500 active personnel, plus a reserve of 479,000:
Numbers: 280,000 - 340,000 including conscripts.
Main Battle Tanks - 3,723, including 973 A1M1 Abrams tanks.
Reconnaissance vehicles - 410.
Armored Infantry Fighting vehicles - 610.
Armored personnel carriers - 4,160.
Artillery pieces 4,480 (including 492 self-propelled, 962 towed).
Mortars - 2,528.
Air Defense surface-to-air missiles - at least 2,100.
Tactical surface-to-surface missiles - over 42.
Numbers: 18,500 including conscripts.
Submarines - 4 tactical patrol submarines.
Surface combatants - 10
Patrol and coastal combatants - 41
* Air Force:
Numbers: 30,000 including 10,000 conscripts.
Combat capable aircraft - 461. 165 fighter aircraft including 26 F-16A, 12 F16-B, 74 MiG-21F and 53 Mirage D/E.
Helicopters - 4 Commando electronic Intelligence
125 Electronic Attack helicopters
* Other Forces:
There are also 150,000 Air Defense Command troops and 397,000 paramilitaries comprising Central Security Forces, National Guard and Border Guard forces.
Sources: Reuters/IISS Military Balance 2010.