The struggle between political forces in Egypt could “lead to the collapse of the state,” the country’s army chief said Tuesday.
In a posting to the army’s Facebook page, General Abdel Fattah al-Sisi said political and economic issues now represented a “real threat” to security.
"The continuation of the struggle of the different political forces ... over the management of state affairs could lead to the collapse of the state," General Abdel Fattah al-Sisi said.
He added that the army would remain "the solid and the cohesive block" on which "the foundation of the state rests."
Al-Sisi, who is also defense minister, also said that the army had been deployed in cities along the Suez Canal primarily to protect the key global trade link.
Islamist President Mohammed Morsi has imposed emergency rule in an attempt to end days of clashes that have left at least 52 people dead.
But Egyptian protesters defied an overnight curfew in restive towns along the Suez Canal, attacking police stations.
At least two men died Monday night or early Tuesday in fighting in the canal city of Port Said, the latest unrest in a wave of violence unleashed last week on the eve of the anniversary of the 2011 revolt that brought down autocrat Hosni Mubarak.
Cairo sky lit by flames
Political opponents spurned a call by Morsi for talks on Monday to try to end the violence. Instead, huge crowds of protesters took to the streets in Cairo and Alexandria, and in the three Suez Canal cities - Port Said, Ismailia and Suez - where Morsi imposed emergency rule and a curfew on Sunday.
"Down, down with Mohammed Morsi! Down, down with the state of emergency!" crowds shouted in Ismailia. In Cairo, flames lit up the night sky as protesters set vehicles ablaze.
The demonstrators accuse Mubarak's successor Morsi of betraying the two-year-old revolution. Morsi and his supporters accuse the protesters of seeking to overthrow Egypt's first ever democratically elected leader by undemocratic means.
Debris from days of unrest was strewn on the streets around Cairo's Tahrir Square, cauldron of the anti-Mubarak uprising.
Youths clambered over a burned-out police van. But unlike on previous mornings in the past few days, there was no early sign of renewed clashes with police.
In Port Said, men attacked police stations after dark. A security source said some police and troops were injured. A medical source said two men were killed and 12 injured in the clashes, including 10 with gunshot wounds.
"The people want to bring down the regime," crowds chanted in Alexandria. "Leave means go, and don't say no!"
Voters backed Islamists
Since Mubarak was toppled, Islamists have won two referendums, two parliamentary elections and a presidential vote.
But that legitimacy has been challenged by an opposition that accuses Morsi of imposing a new form of authoritarianism, and punctuated by repeated waves of unrest that have prevented a return to stability in the most populous Arab state.
The political unrest in the Suez Canal cities has been exacerbated by street violence linked to death penalties imposed on soccer supporters convicted of involvement in stadium rioting in Port Said a year ago, which lead to the deaths of 74 people.
The president announced the emergency measures on television on Sunday. "The protection of the nation is the responsibility of everyone. We will confront any threat to its security with force and firmness within the remit of the law," Morsi said.
His demeanor infuriated his opponents, not least when he wagged a finger at the camera.
Some activists said Morsi's measures to try to impose control on the turbulent streets could backfire.
"Martial law, state of emergency and army arrests of civilians are not a solution to the crisis," said Ahmed Maher of the April 6 movement that helped galvanize the 2011 uprising. "All this will do is further provoke the youth. The solution has to be a political one that addresses the roots of the problem."