GENEVA // The UN's human-rights chief, Navi Pillay, yesterday demanded a wide-ranging investigation into the crackdown by Egyptian security forces on Muslim Brotherhood protesters.
More than 500 people were killed, according to government figures, during Wednesday's assaults on two Cairo protest camps set up by supporters of the ousted Islamist president, Mohammed Morsi.
The Brotherhood has put the death toll at more than 2,000.
It was the worst violence in the country for decades.
"There must be an independent, impartial, effective and credible investigation of the conduct of the security forces," Ms Pillay said. "Anyone found guilty of wrongdoing should be held to account.
"The number of people killed or injured, even according to the government's figures, point to an excessive, even extreme use of force against demonstrators."
Adding her voice to the global outcry over the bloodshed, Ms Pillay urged "all sides in Egypt to step back from the brink of disaster".
"I deplore the loss of life and call on all in Egypt to seek a way out of the violence," she added.
Ms Pillay also urged the Egyptian authorities and security forces "to act with the utmost restraint", saying they were "bound by the rule of law and must act with full respect for human rights".
Earlier yesterday, the Turkish prime minister, Recep Tayyip Erdogan, called on the UN Security Council to meet urgently to discuss the crisis. He said Egypt's leaders should stand a "fair and transparent" trial for what he called a "massacre", which unfolded live on TV.
He again called for the release from custody of Mr Morsi and other members of his government, and said Egypt's current leaders should follow the example of Mohamed ElBaradei, who resigned as Egypt's interim vice president in protest against Wednesday's violence.
* Agence France-Presse, with additional reporting by Associated Press