The political turmoil dividing Egypt threatens the nation's future, the defense minister said, as the instability persists in the Arab world's most populous country.

"The ongoing conflict among the various political forces ... may lead to the collapse of the state and threaten the future of our coming generations," Defense Minister Gen. Abdul Fattah al-Sisi said Tuesday.

Anti-government protesters ignored President Mohamed Morsy's curfew order in cities along the Suez Canal and clashed with police and troops, state-run media reported Tuesday.

In Port Said, about 4,000 people joined the protest, which began at Mariam mosque and continued for hours, winding its way through the streets. They chanted anti-government slogans, at times laced with profanities.

The authorities didn't appear to be detaining any of the demonstrators.

On Tuesday night, the Muslim Brotherhood announced on its Facebook and Twitter pages that the president has delegated authority to either limit or cancel the curfew to governors of Port Said, Ismailia and Suez.

The protests are the latest in the seesaw struggle between Egypt's first democratically elected president and dissidents who say his tenure is a throwback to past dictatorships, particularly the reign of President Hosni Mubarak, toppled in a popular revolt two years ago.

The most recent furor stems from Morsy's declaration of a limited state of emergency for violent hot spots. On Sunday, he announced a 30-day nighttime curfew for the provinces of Port Said, Suez and Ismailia.

Those areas have seen a spate of bloodshed in recent days, starting with the second anniversary of the Egyptian revolution on Friday.

Dissidents angry about the slow pace of change fought with Morsy supporters and police. At least seven people were killed in those clashes.

The tumult intensified a day later, when a judge issued death sentences for 21 Port Said residents for their roles in a deadly football riot last year.

Port Said, which has had a difficult relationship with Cairo over the past six decades, erupted in chaos. At least 38 people were killed in the two days following the verdicts.

Egypt's defense minister has denied reports that the army used live ammunition on protesters, state-run media reported.

Interior Minister Mohamed Ibrahim told police forces Sunday that he understands the challenges and demands they've faced, saying "together with your brothers at the armed forces, you constitute the country's shield and fort in face of all dangers."

"You've faced unprecedented and systematic patterns of violence," he said. "Your security during these confrontations is my goal."

Ibrahim huddled with Prime Minister Hisham Qandil on Monday over state of emergency arrangements, including maintaining peaceful expression, but also dealing firmly with saboteurs targeting police.

The Transport Ministry said that despite the tumult in the Suez Canal region, the unrest has not affected shipping operations to or from the eastern and western ports of Port Said or the traffic at the El Arish port.

Black Bloc labeled terrorist group

Egyptian Prosecutor General Talaat Abdullah has listed one anti-government group, the Black Bloc, as a terrorist entity.

Authorities say its members are often seen wearing black ski masks, waving their trademark black flag while taking part in some of the most violent attacks against police and security forces.

The designation raises the specter of the government taking a more aggressive stance against anti-government protesters.

The group says its mission is to fight government corruption and oppression. The government has often used the Black Bloc's aggressive tactics to depict anti-government protesters as part of an insurgency that wants to topple Egypt's leadership.

Morsy calls for talks

In a speech Sunday night, Morsy decried the behavior of "criminals," saying recent violence "does not have anything to do with the Egyptian revolution. ... In fact, it is against the revolution."

But he acknowledged the legitimate dissent in Egypt, saying "dialogue is the only way to bring about stability and security."