Egypt's ruling generals have denied allegations that they deliberately attacked a peaceful protest on Sunday night, even though evidence of military involvement in the death of 26 people continues to grow.

"The armed forces would never, and has never, opened fire on the people," said Mahmoud Hegazy, a member of the Supreme Council of the Armed Forces (Scaf), which has run the country since the fall of Hosni Mubarak in February.

Assistant defence minister Major General Adel Emara insisted the military showed "self restraint" during Sunday's street fighting. "Never did a man from the armed forces run over anyone," said Emara during a rare public press conference put on by the junta.

But the generals' claims are directly contradicted by an increasing number of video clips, eyewitness testimonies and medical reports that suggest military personnel attacked protesters with guns and armoured personnel carriers, killing many – mainly Christian Coptic protesters – and wounding hundreds in the process.

On Wednesday, Amnesty International declared that the army must answer for Sunday's "bloodbath" and said the top brass should stop trying to evade responsibility by blaming shadowy "foreign conspiracies" for the unrest.

"One can only wonder what orders were given that could have led to military vehicles running down protesters on the streets," argued the human rights organisation. "If the military police and other security forces were not acting under orders, it raises questions about their ability to police demonstrations in the first place."

In Cairo, those who witnessed Sunday's events reacted with anger and incredulity at Scaf's continued insistence that trouble originated with protesters, not the armed forces – an argument the generals attempted to back up with a highly selective display of video footage.

"After seeing such unprovoked aggression and extreme violence against protesters, the sight of them [Scaf] up there in a press conference equivocating and trying to buy their way out of trouble with video clips and lectures was absolutely disgusting," said Sherief Gaber, a 27-year-old activist. "What's worse is that they are trying to win a short-term PR victory at the expense of igniting fascist violence throughout the country. It will be a pyrrhic victory for them, if it's a victory at all."

A fierce struggle has broken out in a bid to shape the narrative over what happened on Sunday night: the junta insists its forces were dragged into sectarian street battles, while demonstrators claim Scaf provoked the turmoil in order to crack down on revolutionary opposition from Christians and Muslims alike.

The generals devoted much of the press conference to accusing a Coptic priest of inciting violence by calling for an "unprecedented" protest march to the state television building. They also deployed the rhetoric of religious unity. "Egypt's Copts are part of the fabric of this society. All Egyptians are citizens with the same rights and obligations," said Hegazy.

"The power of the Egyptian people is in its unity. Egypt was never more in need of unity than it is now. The armed forces belong to the people, whether Christian or Muslim." His comments followed a statement by Pope Benedict XVI, who said he was deeply saddened by recent disturbances in Egypt.

Scaf defended the role of state television in the unrest following widespread criticism of news presenters who implied the armed forces were coming under attack by Christian militants. "This is a word of truth: we don't have any influence on state coverage," claimed Major General Ismail Etman.

"We don't tell them what to cover and what not to cover. We don't oppress opinions. The media is not politicised or militarised." Yet the state media's version of events is being challenged on a wide range of independent blogs and websites, where interviews with survivors and mobile phone and amateur camera footage are being circulated swiftly. Portals such as Mosireen.org and Maspero Testimonies have collated accounts which appear to make the military's official position on Sunday's bloodshed untenable. Whether Egyptians are receptive to the dissent remains to be seen, however.

"The anger at Scaf among the activist community is one thing, but there are a large proportion of people who are buying into or even participating in this violence," said Gaber. "Most people are completely terrified and they're willing to believe the coverup because it's easier to accept that than to accept the fact that murderers are ruling your country."