CAIRO, Egypt (CNN) -- Egypt and its capital Cairo, teetered on the edge early Thursday as clashes persisted following the bloodiest day since the revolution two years ago that was envisioned to bring peace and democracy to Egypt -- but has not.
The violence Wednesday pitted Egypt's military and current government against backers of deposed President Mohamed Morsy, though others also were caught in the fray.
At least 278 people were killed, including 235 civilians, state TV reported, citing an Egyptian emergency official. Interim Interior Minister Gen. Mohammed Ibrahim said that an additional 43 police officers died.
"It's an open war," said a protester who escaped one of two Cairo camps that were raided.
The intensity and violence lingered into Thursday morning, when state TV reported Morsy backers were attacking police stations, hospitals and government buildings despite a government-mandated curfew. More Egyptian troops were being deployed at entrances to Cairo and Giza, with the unrest prompting the closure Thursday of banks and the nation's stock market.
The 2011 revolution that led to the ouster of Hosni Mubarak, who'd kept a firm grip on power for 30 years, was followed by Egypt's first democratic elections. Morsy -- a leader of the Islamist group the Muslim Brotherhood -- won the presidency in that 2012 vote, but was forced out by the military last month.
Morsy hasn't been seen since he was taken into custody. Yet his supporters have very public in voicing their opinions, massing on the streets of Cairo and elsewhere to slam military leaders and demand Morsy's return to the presidency.
Egypt's new government refused to back down, criticizing elements of the protest movement and specifically ordering them to leave two spots where they'd been gathering in Cairo for six weeks, or else they'd force them out.
On Wednesday, they did.
The story of what exactly transpired -- who attacked whom, who opened fire, who was to blame -- varied 180 degrees depending on where one stood in the debate over Egypt's past, present and future.
On the one side, there were Morsy supporters, one of whom accused government forces of waging a "full-on assault" on what they said had been, to-date, peaceful demonstrations. On the other, there were those like Ibrahim, who professed to being "surprised" by the "Muslim Brotherhood's (decision) to attack the security forces."
What couldn't be mistaken was the chaos, the bloodshed and the sense -- even with Prime Minister Hazem Elbeblawi's pledge "we hopefully will rebuild our nation" -- that the already volatile situation in Egypt could be getting worse.
"I think what we're seeing right now is just the beginning of what is promising to be a very, very long and bloody battle as the interim government and the security forces try to regain control of the streets," CNN's Arwa Damon reported from Cairo.
The government on Wednesday, according to state TV, issued a month-long state of emergency. This a loaded term in Egypt, given that Mubarak long ruled under such a decree that barred unauthorized assembly, restricted freedom of speech and let police jail people indefinitely.
The prime minister said the government felt compelled to act to ensure stability, praising security forces for their "calm" and claiming some activists had intent to undermine the government.
"We are here to build a democracy based on justice," Elbeblawi said. "... We have to reason and use common sense. We are all part of this nation."
Yet not everyone expressed faith in his government.
Mohammed ElBaradei -- a secular leader who was one of Morsy's biggest critics before joining the government that replaced him -- submitted his resignation Wednesday as vice president of foreign affairs, saying he didn't agree with decisions being carried out by the ruling government and "cannot be responsible for a single (drop of) blood." His decision spurred scorn from some former allies, with youth groups and June 30th coalition members questioning his stepping down "at this critical and historic phase," according to state-run EGYNews.
Kenneth Roth, the executive director of Human Rights Watch, sharply criticized "ongoing violence" by Brotherhood supporters against Coptic Christian churches in the country. He also chastised the government's crackdown on the Islamist group.
"Didn't have to happen," Roth tweeted. "MB had right to protest. No need for massive lethal force."
The European Union's top diplomat, Catherine Ashton, urged "security forces to exercise utmost restraint and ... the interim government to end the state of emergency as soon as possible, to allow the resumption of normal life."
In light of the ongoing violence, the United States is considering canceling next month's planned biennial military training exercise with Egyptian forces, an official in President Barack Obama's administration said.
Pressing Egypt's government "to respect basic human rights," U.S. Secretary of State John Kerry said that Wednesday's "deplorable" events "run counter to Egyptian aspirations for peace, inclusion and genuine democracy."
"The path toward violence leads only to greater instability, economic disaster and suffering," he said.
For weeks, the two makeshift Cairo protest camps had become cities unto themselves -- with people sleeping in tents, vendors hawking everything from haircuts to masks, and children playing in inflatable castles and splashing in kiddie pools. At dawn on Wednesday, they came under siege.
Security forces rushed in, bulldozing tents and escorting away hundreds. Some mothers and fathers managed to whisk away their children, gas masks on their faces.
Within three hours, the smaller camp -- Nahda, near Cairo University -- was clear, except for shreds of torn-down tents that remained.
But the larger protest, near the Rabaa al-Adawiya mosque in eastern Cairo, proved trickier. Facing heavy resistance, the military called in special forces.
Chaos ensued. Along with smoke, bursts of rapid gunfire filled the air, as did people's wails. Many protesters refused to leave, even in the face of bulldozers and surrounded by the injured and dead.
"They said they're prepared to die," CNN's Reza Sayah reported.
State TV reported that snipers from the Muslim Brotherhood -- Morsy's party -- exchanged gunfire with Egyptian security forces near a university building.
The dead included cameraman Mick Deane, who'd worked for UK-based news channel Sky News for 15 years and for CNN before that. Habiba Abdel Aziz of Gulf News, who was in Egypt on her own time having celebrated the Eid holiday, also died, editor-at-large Francis Matthew told CNN.