Tahrir Square: Egypt orders probe into Cairo clashes
Egyptian officials have ordered a probe into overnight clashes between police and protesters in Cairo's Tahrir Square that left hundreds of people injured.
Riot police used tear gas to disperse hundreds of demonstrators, who pelted officers with stones and fire bombs.
Fresh clashes broke out on Wednesday as angry crowds demanded action over the previous night's unrest.
The riots are the most serious violence in Egypt in weeks - officials say more than 1,000 people were injured.
Activists are calling for the speedy implementation of reforms demanded during the revolution that toppled President Hosni Mubarak in February.
They also want senior officials to face justice for the deaths of 850 protesters during the uprising, including Mr Mubarak himself, who is due to stand trial on 3 August.
After a long night of fighting, Egypt's Prosecutor General, Abdel Meguid Mahmoud, ordered the formation of a committee to investigate the clashes in Tahrir Square - the epicentre of the Egyptian protest movement.
The announcement came hours after the interior minister ordered police to leave the square in an attempt to avoid any further violence.
"The regrettable incidents in Tahrir Square... are designed to destabilise the country and pit the revolutionaries against the police," the Supreme Council of the Armed Forces - Egypt's ruling military council - said in a statement.
But some angry demonstrators have remained in the square, says the BBC's Jeannie Assad in Cairo.
There were more scenes of violence as youths threw stones and other missiles at the police, who responded with tear gas.
Protesters outside the interior ministry demanded the resignation of several key figures over Tuesday's violence - including the head of the military council, Gen Mohamed Tantawi, and the Minister of the Interior, Mansour Essawi.
"I am here today because I heard about the violent treatment of the police to the protesters last night," said accountant Magdy Ibrahim.
Another protester said police tactics had not changed since the revolution, despite promises that the country's hated security forces would be dismantled and reformed.
"They're still using an iron fist against us," he said.
'Fuelling the fire'
There are conflicting reports as to how Tuesday's clashes began.
Some witnesses say they started outside the interior ministry, where bereaved families were demonstrating against what they perceive as the slow prosecution of security officers alleged to be responsible for the deaths of hundreds of protesters.
Violence then spread to Tahrir Square as other people joined in and threw stones at the security forces, they say.
Mazzly Hussein, who took part in the protests which unseated Mr Mubarak, said the police force was "as violent and as brutal as ever".
"Families of martyrs were attacked and a lot of them were arrested and when they demanded the release of the arrested young men, all hell broke lose and the violence started," she told the BBC.
However, others claim the conflict started when a group of "thugs" attacked a gathering at a Cairo theatre to honour those killed during the uprising earlier this year.
"These aren't revolutionaries, they have no clue about the revolution, politics or anything else. They're here to destroy, nothing more," said one man at the scene.
"Egypt is now falling apart. Why?" said another angry witness. "Because [the protesters] are fuelling the fire."
Deputy Health Minister Abdel Hamid Abaz told the Mena state news agency more than 1,000 people had been injured over the past two days - 120 people had been taken to hospital, he said, and 16 people were still being treated.