CAIRO -- Clashes between Egyptian security forces and supporters of ousted President Mohammed Morsi left at least 65 people dead, the health ministry reported Saturday, as both sides appeared to harden their resolve and doubts grew about the chances for national reconciliation.
The bloodied and mangled bodies of dozens of Mr. Morsi's Islamist supporters lined the floors of an improvised hospital in eastern Cairo after security forces launched an attack against demonstrators calling for his reinstatement.
The violence came a day after prosecutors said they were investigating the former president on allegations of espionage and murder, and millions took to the streets to heed the military's call for Egyptians to give the armed forces the popular "mandate" to combat "terrorism."
The Muslim Brotherhood, which supports Mr. Morsi, put the toll higher than the state's account, saying that at least 120 people were killed and thousands injured when police and plainclothes men opened fire with live ammunition and tear gas on demonstrators who had expanded their protest onto two major highways.
Mr. Morsi's supporters said the military appeared intent on shooting them into submission -- or even wiping them off the country's political map, as judicial authorities leaked further allegations against Muslim Brotherhood leaders to local media.
But the overnight violence did little to clear the sprawling tent city of Morsi supporters in eastern Cairo's Nasser City district, where many have camped for nearly a month. Demonstrators said Saturday they would stay put until Mr. Morsi resumed power, although many also said they anticipated further violence in the days ahead.
The political crisis appeared to be quickly moving beyond the point of negotiations and reconciliation between the ruling generals and the ousted leaders of the Muslim Brotherhood.
The Muslim Brotherhood may be losing control of its followers, who have grown increasingly angry.
U.S. Secretary of State John F. Kerry warned of the political repercussions of Egypt's ongoing crackdown.
"At this critical juncture," Mr. Kerry said in a statement, "it is essential that the security forces and the interim government respect the right of peaceful protest, including the ongoing sit-in demonstrations."
Egypt's Interior Minister Mohamed Ibrahim on Saturday denied that his troops had fired on protesters, but he indicated that the country's security forces planned to press on with a strategy to clear the pro-Morsi demonstrations that have shut down roads and squares in the capital since the July 3 coup.
He said the protesters would be dispersed "soon." from a pro-Morsi camp near the Rabaa al-Adawiya mosque in eastern Cairo.
In a signal of a broader crackdown, Mr. Ibrahim also said the state's vast internal security apparatus, which had been handicapped after the 2011 uprising that ousted President Hosni Mubarak, would again begin monitoring political and religious activities, as it had under Mubarak. Such security apparatus was known for carrying out torture and forced disappearances.
Police later released a video that showed demonstrators hurling rocks at security forces and setting fires. At least one man fired a gun.
Judicial authorities told independent newspaper Al-Masry Al-Youm on Saturday that they were investigating jailed Muslim Brotherhood leaders in connection with the overnight violence, alleging that the group had hired snipers to shoot its own followers.
Egyptian security forces have detained hundreds of Morsi supporters, including a number of top Muslim Brotherhood officials and presidential aides, since the coup.
Prosecutors said Friday that they had launched an investigation into allegations that Mr. Morsi had conspired with the militant Palestinian organization Hamas in a 2011 prison break that freed him and about 30 other Muslim Brotherhood members amid the chaos of the uprising that ousted Mubarak.
The Brotherhood and Hamas separately denied the charges, dismissing them as politically motivated.
The allegations, which also included murder and kidnapping, marked the state's first official steps toward prosecuting Mr. Morsi.
The military has held Mr. Morsi, Egypt's first democratically elected president, incommunicado in an undisclosed location since the his ouster. Military officials indicated to the Associated Press on Friday that they were leading the investigation against him and had interrogated him repeatedly in the past three weeks.
Egypt's interim Vice President Mohamed ElBaradei, a liberal political leader, who has been relatively silent on the conditions of Mr. Morsi's detention, spoke out on Twitter on Saturday to condemn the recent violence, hinting at divisions within the country's still nascent cabinet.
"I strongly condemn the excessive use of force and the killing of victims. I am working tirelessly and in all possible directions to end the confrontation in a peaceful manner," Mr. ElBaradei wrote
Meanwhile, grief and shock mingled with outrage in the chaotic rooms of the makeshift hospital at the Brotherhood-led protest camp.
Pools of blood congealed on the floors, as men wept over the bodies of slain relatives, and exhausted volunteer doctors rested amid blood-spattered sheets and battered equipment. Doctors at the field hospital said many of the dead had received gunshot wounds to the head or torso.
Doctors and witnesses said the wounded began streaming in at about 11 p.m. Friday, as groups of protesters on a nearby highway and outside Cairo's al-Azhar University came under attack.
At first, most of the victims were suffering from the suffocating effects of tear gas, then later, birdshot wounds, and later still gunshot wounds, doctors said.