At least 41 people injured after clashes breakout during rival rallies in Cairo's Tahrir Square after Friday prayers.
"Clashes have erupted in Cairo's Tahrir Square as supporters and opponents of Egyptian President Mohamed Morsi tried to wrest control of the iconic square in rival rallies.
The state news agency on Friday cited a doctor at a hospital near Tahrir saying 41 people have been injured as protesters showered stones at each other in some of the worst violence over the country's new leader.
The clashes started after Brotherhood supporters tore down a podium belonging to a group that was chanting anti-Morsi slogans, witnesses said.
Morsi's supporters, mainly his powerful Muslim Brotherhood movement, had called their rally to denounce this week's acquittals of Hosni Mubarak-era officials.
His opponents, a coalition of liberal and secular leaning groups, had previously called their own rally to denounce Islamist control over a body drafting the new constitution, and Morsi's performance in office.
"Down with the Supreme Guide's rule," Morsi's opponents chanted, referring to Muslim Brotherhood leader Mohammed Badie.
Confusion reigned in the large square, the nerve centre of protests that toppled Mubarak early last year, as fighting broke out in several areas of the central Cairo hub.
Al Jazeera's Sherine Tadros reporting from Cairo said that the clashes had intensified.
"The clashes were taking place just off Tahrir Square and on the side streets ... they are now happening right in the centre of the square.
"People [have been] throwing rocks and stones at each other and this is what we have been seeing ... and 12 people have been injured because on the side streets it has been a lot more intense," she said....."