Egypt’s military chief warned on Tuesday that the political crisis sweeping the country could lead to the collapse of the state.

Egypt's military chief warned on Tuesday that the political crisis sweeping the country could lead to the collapse of the state, as thousands defied curfews and the death toll from days of rioting rose to 52.

"The continuing conflict between political forces and their differences concerning the management of the country could lead to a collapse of the state and threaten future generations," General Abdel Fattah al-Sissi, who is also defense minister, said on his Facebook page, vowing to defend vital infrastructure, including the Suez Canal.

Sissi's warning comes as medics on Tuesday reported another three people killed in the violence sweeping Egypt, pushing to at least 52 the death toll from five days of clashes.

Two people died in fighting between protesters and security forces in the riot-hit canal city of Port Said, and one was shot dead in Cairo when protesters and police clashed near Tahrir Square, the capital's iconic hub of protest.

Despite the month-long state of emergency and night-time curfews on Port Said, Ismailiya and Suez imposed by President Mohammad Mursi, thousands of demonstrators flooded the streets of the three Suez Canal cities Monday night.

The protesters chanted slogans against Islamist rule in Egypt, "Fall, fall the rule of the guide (of the Muslim Brotherhood), referring to Mursi, who hails from the Brotherhood.

Egypt has already deployed troops to Port Said and Suez provinces, at each end of the canal that Sissi said the army would defend.

"The deployment of the army in Port Said and Suez aims to protect strategic infrastructure, especially the Suez Canal, which we will not allow to be harmed," Sissi said.