CAIRO The head of the Egyptian military warned political conflict could lead to the collapse of the state and said protecting the Suez Canal was one of the main objectives of the army deployment to nearby cities shaken by violence.
Protesters defied a curfew in towns along the Suez Canal overnight, attacking police stations after President Mohamed Mursi imposed emergency rule to end days of clashes that have killed at least 52 people.
The remarks of General Abdel Fattah al-Sisi, who is also defence minister, were published on the official Facebook page of the army spokesman.
He said the economic, political and social challenges facing Egypt represented "a real threat to the security of Egypt and the cohesiveness of the Egyptian state" and the army would remain "the solid and cohesive block" on which the state rests.
The army, he said, belonged to all Egyptians regardless of their sect or political affiliation.
"The continuation of the struggle of the different political forces ... over the management of state affairs could lead to the collapse of the state," he said.
"The army's deployment in Port Said and Suez provinces aims to protect the vital strategic interests of the state, at the forefront of which is the vital Suez Canal," he said, adding the army would not allow the canal to be harmed.
The military assumed power from deposed President Hosni Mubarak at the height of the uprising against him in 2011 before leading the state through an interim period that formally ended with Mursi's election in June last year.
Our top photos from the last 24 hours.