al-Jazeera: Hundreds of soldiers and security troops backed by armoured vehicles stormed into the square at around 3am on Saturday, firing shots into the air, brandishing tasers and batons, and beating people, witnesses said.
Tens of thousands of protesters had flooded into the square on Friday in one of the largest demonstrations since former Mubarak stepped down on February 11.
The protesters called for the Supreme Council of the Armed Forces, which nows runs the country, to honour their demands, which include prosecuting a number of former high-ranking regime officials and Mubarak himself.
The protesters had been joined by perhaps as many as 20 military officers, who had been under orders not to participate. Demonstrators stayed in the square past the military curfew, which which runs from 2am to 5am, saying they wanted to protect the officers who joined.
When security forces stormed the square, some of the protesting army officers managed to escape, while others were arrested, witnesses said.