CAIRO, Egypt -- Security forces and armed men clashed with supporters of Egypt's ousted president early Saturday, killing at least 65 protesters in mayhem that underscored an increasingly heavy hand against protests demanding Mohammed Morsi's return to office.
In chaotic scenes, pools of blood stained the floor and bodies were lined up under white sheets in a makeshift hospital near the site of the battles in eastern Cairo. Doctos struggled to cope with the flood of dozens of wounded, many with gunshots to the head or chest.
It was the deadliest single outbreak of violence since the military ousted Morsi on July 3 and one of the deadliest in 2 1/2 years of turmoil in Egypt.
The extent of the bloodshed pointed to a rapidly building confrontation between the country's two camps, sharply divided over the coup that removed Egypt's first freely elected president after widespread protests against his rule.
Authorities talk more boldly of making a move to end weeks of protests by Morsi's largely Islamist supporters. At the same time, the Islamists are growing more assertive in challenging security forces as they try to win public backing for their cause.
Saturday's clashes were sparked when pro-Morsi protesters sought to expand their main Cairo sit-in camp by moving onto a nearby main boulevard, only to be confronted by police and armed civilians -- reportedly residents of nearby neighbourhoods. Police initially fired tear gas but in ensuing clashes, the protesters came under gunfire.
Officials from Morsi's Muslim Brotherhood and their allies decried what they called a new "massacre" against their side, only weeks after July 8 clashes with army troops in Cairo that left more than 50 Morsi supporters dead.
U.S. Secretary of State John Kerry said that he spoke to Egyptian authorities, saying it is "essential" they respect the right to peaceful protest. He called on all sides to enter a "meaningful political dialogue" to "help their country take a step back from the brink."
But neither side has shown much taste for reconciliation. Islamists staunchly reject the new leadership and insist the only possible solution to the crisis is to put Morsi back in office. Meanwhile, the interim leadership is pushing ahead with a fast-track transition plan to return to a democratically elected government by early next year.
And the military-backed authorities appear confident of public support for a tougher hand after millions turned out for nationwide rallies Friday called by army chief Gen. Abdel-Fattah el-Sissi as a mandate against "terrorism and violence."
Interior Minister Mohammed Ibrahim, who is in charge of police, took an uncompromising stance in a press conference after the violence. He accused the pro-Morsi side of provoking bloodshed to win sympathy.
"We didn't go to them, they came to us -- so they could use what happened for political gain," he said. Ironically, Ibrahim is originally a Morsi appointee, and his then-boss praised him for a tough hand after police killed dozens of anti-Morsi protesters in the city of Port Said earlier this year.
"The Ministry of Interior never has and never will fire on any Egyptian," he added, saying police only fired tear gas in Saturday's violence.
He suggested authorities could take the more explosive step of moving against the two main pro-Morsi protest camps in Cairo: weeks-old sit-ins, on outside the Rabaah al-Adawiya in eastern Cairo and another in Nahda Square in Cairo's sister city of Giza.
He depicted the encampments as a danger to the public, pointing to a string of 10 bodies police have said were found nearby in recent days. Some had been tortured to death, police have said, apparently by members of the sit-ins who believed they were spies.
"Soon we will deal with both sit-ins," Ibrahim said.
Interim Vice-President Mohamed ElBaradei, a longtime pro-democracy campaigner who backed the military's ouster of Morsi, raised one of the few notes of criticism of Saturday's bloodshed.
"I highly condemn the excessive use of force and the fall of victims," he wrote in a tweet, though he did not directly place blame for the use of force. He added that he is "working very hard and in all directions to end this confrontation in a peaceful manner."
But the image of the Islamists as dangerous and not the peaceful protesters they contend they are has had a strong resonance. Over past weeks, there have been cases of armed Islamist Morsi backers attacking opponents -- though the reverse has also occurred. Before Saturday, some 180 people had been killed in clashes nationwide.
Walid el-Masry, one of founders of the youth activist Tamarod movement that led the original wave of protests against Morsi, said he believed the Brotherhood "pushed for (the) clashes. ... The Muslim Brotherhood is trying to grab the international attention and have the victim attitude."
The liberal umbrella group National Salvation Front, which ElBaradei once led, also said it "puts strong blame on the Brotherhood," pointing to hard-line rhetoric in speeches at pro-Morsi rallies calling for "jihad" and "martyrdom."
A leading figure of Morsi's Muslim Brotherhood, Mohammed el-Beltagy, accused army chief el-Sissi of seeking violence by calling Friday's pro-military rallies.
"This is the mandate el-Sissi took last night -- to commit massacres and bloodshed against peaceful protesters denouncing the military coup," el-Beltagy said in a statement on his Facebook page.
The clashes began after a crowd of Morsi supporters late Friday moved out of their Rabaah al-Adawiyah encampment and installed themselves on a nearby major thoroughfare, blocking it. They began to set up tents there, planning to stay there at least three days, said Mahmoud Zaqzouq, a Brotherhood spokesman.
Police moved in and fired tear gas to break up the crowds at around 2 a.m., and protesters responded with volleys of stones in battles near a memorial to former President Anwar Sadat, who was assassinated in 1981.
Gunshots also rang out, seemingly from both sides, said one witness, Mosa'ab Elshamy, a freelance photographer, though he could not tell who started firing.
Armed residents of the area also joined the police side, and there were also plainclothes police carrying handguns, he said.
"They aimed at killing the people. They aimed the head and the neck," said Ahmed Abdullah, a doctor at a field clinic set up at Rabaah al-Adawiya, as he wiped away tears.
At the Rabaah al-Adawiya clinic, men shouted "God is great," and women wailed as bodies were loaded into ambulances to be taken for examination at hospitals. Bodies of more than a dozen men lay on the blood-splattered floor with white sheets over them.
Ragab Nayel Ali, one of the pro-Morsi protesters, said security forces fired first with tear gas and birdshot. "Protesters replied by hurling rocks and started building walls," said Ali, who was injured in an accident as he ferried wounded on his motorcycle from the fighting to a field hospital.
Health Ministry spokesman Khaled el-Khateeb said that at least 65 people were killed and 270 wounded. Nine more were killed in clashes in the Mediterranean city of Alexandria since Friday, he said.
A Brotherhood spokesman, Ahmed Aref, told reporters that 66 were killed in the Cairo violence and another 61 were "clinically dead." He did not further explain their condition.
The Interior Ministry said 14 policemen were wounded, two with gunshot wounds to the head.
Clashes in Alexandria erupted on Friday and extended into the night as more than 100 Morsi supporters took refuge in a central mosque, holding captive 17 of their rivals as they tried to fend off a security siege of the building. A security official said the hostages were freed and those inside the mosque arrested. The official spoke on condition of anonymity because he was not authorized to speak to the media.