Supporters of Egyptian President Mohamed Morsi scuffled with opponents in Cairo's Tahrir Square on Friday in the worst violence since Egypt's new Islamist leader took office this year.
Liberal and leftist groups had called Friday's protest to demand more action from Morsi after his first 100 days in office.
The demonstration fell far short of the 'Million Man March' that organizers had been calling for. But large clusters of young men blocked traffic, shouted slogans for and against the president, and threw rocks at each other.
Gunshots were fired during the skirmishes, but the shooting did not last long. Arab TV reported that a number of protesters were hit on the head by rocks. The health ministry said at least 12 people were wounded.
Anger over Morsi move
The street demonstrations came amid a political tug-of-war between the president and opposition parties over a decision by Morsi to remove Prosecutor General Abdel Maguid Mahmoud on Thursday.
The removal followed a court acquittal of loyalists of ousted President Hosni Mubarak accused of organizing a brutal attack on protesters last year. Mahmoud was appointed by Mubarak.
On the streets Friday, pro-Morsi supporters chanted that the "people want to cleanse the judiciary," while opponents shouted that the "people want to topple the president."
One Morsi supporter said the judiciary needs to be purged of Mubarak-era appointees.
"There should be a cleansing of the judiciary right away after the dismissal of the prosecutor general, so that there will be retribution for the blood of the martyrs who died for the revolution from the 25th of January up until the parliament incident," he said.
Muslim Brotherhood supporters of the president tore down a makeshift platform in Tahrir Square that had been set up by liberal political parties which oppose him.
"Protesters were on the stage and then suddenly we found President Morsi supporters attacking the stage and beating everyone," said government opponent Ashraf al-Said. "I come here today for the sake of Egypt, my country. I am not here for Morsi or other factions. What is going on here is unfair."
Morsi under fire
Egypt's Fraternity of Judges issued a statement in support of the fired prosecutor general.
Egypt's president has the power to appoint the country's top judge, but not to fire him. Morsi appears to have skirted the process by appointing Mahmoud as Ambassador to the Vatican.
Nancy Okail, director of Freedom House's Egypt office in Cairo, said that the acquittals are causing "obvious dismay" for President Morsi. But she said that does not give the president the legal authority to remove his prosecutor general.
"The president does not have the right to dismiss the public prosecutor or any legislative authority unless there is a crime or there is a low case against him," she said. "The public prosecutor can resign, but he cannot be dismissed."