Nearly 60 people have died in the latest wave of unrest. In Cairo, one protester died of gunshot wounds as youths hurled stones and police fired tear gas into the night near Qasr el-Nil Bridge, a landmark over the Nile next to major hotels. In nearby Tahrir Square, protesters set fire to a police armored personnel carrier.
A state of emergency was declared Sunday in the three Suez Canal provinces that were hit hard after the weekend unrest, sparked in part by death sentences for 21 defendants involved in a mass soccer riot a year ago. The violence first erupted Thursday and was catalyzed Friday by protesters marking the two-year anniversary of the start of the anti-Hosni Mubarak uprising that left 11 dead, most of them in Suez.
The curfew is Morsi's attempt to contain the five days of violence. He said he had instructed the police to deal "firmly and forcefully" with the unrest and threatened to do more if security was not restored.
But many strongly feel that the curfew is unjust.
"We completely reject Morsi's measures. How can we have a curfew in a city whose livelihood depends on commerce and tourism?" said Ahmed Nabil, a schoolteacher in the Mediterranean coastal city.
Crowds marched through the streets of Port Said on Monday evening, chanting, "Erhal, erhal," or "Leave, leave" - a chant that was first heard during the 18-day uprising that toppled Mubarak in 2011 but is now directed at Morsi.
Morsi, who hails from the Islamist group Muslim Brotherhood, has been in office for a turbulent seven months. The geographical spread of the unrest and the tenacity of the protesters have showcased the depth of opposition to Morsi's rule outside the ranks of the Brotherhood and other Islamist groups.
After initial resistance, dialogue between The Front, the president's main political opposition, and Morsi to end the crisis went ahead late Monday afternoon. But a list of participants released later by the presidential palace showed that Morsi presided over an inaugural session made up almost entirely of fellow Islamists whose support for him has never been in question.
The Front is led by leader and Nobel Peace Laureate Mohamed ElBardei. The group wants to leverage the turmoil to break the Islamists' power and force Morsi to make concessions.
"We support any dialogue if it has a clear agenda that can shepherd the nation to the shores of safety," said ElBaradei, flanked by former Arab league chief Amr Moussa and leftist Hamdeen Sabahi.
The Front later issued a statement in which it said failure by Morsi to meet its conditions should be cause for early presidential elections, now scheduled for 2016. The Front is also calling for mass, nationwide protests on Friday.
The Associated Press contributed to this report.