Egypt’s military chief warned Tuesday of a potential “collapse of the state” after a fourth night of violent street battles between protesters and Egyptian security forces in Cairo and other major cities, heightening the prospect that the country’s military might be forced to intervene.

The warning from Abdel Fatah al-Sissi, who also serves as defense minister, indicated that troops could be pressed into action soon, analysts said. But it remained unclear on whose behalf the generals might interfere, underscoring the lingering questions about the scope of President Mohamed Morsi’s control over the armed forces and state institutions that once answered to Hosni Mubarak.

“The continuation of this struggle between the different political forces . . . could lead to the collapse of the state and threatens the future of coming generations,” Sissi told military academy cadets, according to remarks posted on the armed forces’ Facebook page Tuesday.

At least 54 people have died, and hundreds more have been injured, in five days of bitter clashes between anti-government protesters — many armed with rocks, molotov cocktails and, in some cases, live ammunition — and the better-armed security forces.

On Tuesday, residents said tanks and other military vehicles had fanned out on the streets of Port Said, a strategic city of 600,000 at the tip of the Suez Canal, where the violence has been the worst. Troops in Port Said and Suez stood by as thousands took to the streets overnight in defiance of a 9 p.m.-to-6 a.m. curfew and state of emergency declared by Morsi.

TIMELINE: Key events in Egypt since the fall of Hosni Mubarak.

Egypt’s weak and poorly trained police force has struggled to quell the violence that started Friday, after protesters marched through Cairo and several other cities to voice their opposition to Islamist rule under Morsi on the two-year anniversary of the uprising that ousted Mubarak.

The anti-government frenzy spread to Port Said a day later, after a court imposed death sentences on 21 locals for their alleged roles in a deadly soccer riot last year. Anger there, as in Cairo, spurred clashes, and then deaths, in a cycle that quickly roused thousands more protesters to participate and has expanded an opposition movement previously segmented along religious and class lines.

Many Egyptians, including the Islamists, say that the country’s abusive Interior Ministry forces — epitomized by the black-clad riot police used to suppress protests — have changed little since the Mubarak era. In the days since the unrest began, even ranking members of the Muslim Brotherhood, which backs Morsi, have acknowledged that police may have used excessive force.

“The police force is largely dysfunctional and has been very hesitant since the revolution. It is not trained to deal with protests,” said Gehad el-Haddad, a senior Muslim Brotherhood adviser.

That leaves the army — better trained and more widely respected, Haddad and others say — as a potential referee if the crisis continues to spin out of control. But how the army would intervene remains a matter of debate.

Morsi declared a 30-day state of emergency and nighttime curfew along the Suez Canal on Sunday, a day after deploying the army to guard government installations in Port Said and Suez.

The moves failed to stop the violence, which spilled into a fifth day Tuesday, as protesters in Cairo battled police on a main bridge adjacent to Tahrir Square, and demonstrations erupted in defiance of the curfew in Port Said, Suez and Ismailia.Haddad said this time would be different. “This time they’re not running the game. They’re obeying the orders of a commander in chief,” he said, referring to the troops and Morsi.

Political analysts and activists interpreted Sissi’s remarks Tuesday as a warning to the perpetrators of violence as well as a signal that the military could soon stage a broader intervention, as it did during the uprising in 2011.

At the start of that revolt, anti-Mubarak protesters engaged in fierce street battles with police forces, before the latter withdrew from the streets and cleared the way for the military rule that continued for nearly a year and a half after Mubarak’s fall.

Some analysts have speculated that Sissi, who was promoted by Morsi to head the military as other senior generals were forced out, is far more loyal to the Islamist government than the previous generals would have been.

“A coup isn’t possible at the moment or the medium-term,” said Khalil al-Anani, a Middle East scholar at Britain’s Durham University.

Others aren’t so sure.

The military is fundamentally neutral, said Sameh Seif el-Yazal, a retired general and military analyst in Cairo. That the army took control of the country and faced its own opposition in Tahrir Square has left it deeply unwilling to do so again, he said. But if it does, it’s unlikely to do Morsi’s bidding. “Morsi cannot order the units and barracks of different forces in Egypt to do whatever he wants,” Yazal said.

But the crisis, Yazal and others said, is likely to escalate.

Opposition leaders have refused to participate in a dialogue with Morsi unless he meets their conditions of forming a national unity government and amending articles of the recently ratified constitution, which critics say has opened the door to a broader implementation of Islamic law.

The president’s office rejected those demands Tuesday. “Forming a national rescue government with these criteria would require a long time,” said Pakinam el-Sharkawy, a presidential adviser, at a Cairo news conference after a dialogue session with various political groups that was mostly boycotted by the anti-Islamist opposition. Egypt is slated to hold parliamentary elections in a few months, Sharkawy noted, and she urged parties to focus on dialogue and elections.

Morsi will travel on Wednesday and Thursday to France and Germany, where he is expected to meet with state officials to discuss Egypt’s imperiled economy. Those plans have sparked further criticism from liberal activists, who say Morsi is not taking the unrest seriously.

The National Salvation Front, a loose alliance of opposition groups, has called for a renewed bout of mass protest Friday.

In Tahrir Square, where the numbers thinned Tuesday despite clashes nearby, activists weighed their options. Some said their opposition to Morsi had grown so intense that they might accept a military coup. A few protesters in Port Said said they would go as far as to welcome U.S. intervention.

Others were wary.

“The question is, what is [the military] going to do? Now they are neutral, but if and when it gets serious, will they stand with us?” said Hadeel Mohammad, a 33-year-old unemployed protester. “Unfortunately, we won’t win unless the military joins us.”