At least one person was killed when Egyptian riot police stormed Cairo's Tahrir Square late Tuesday to disperse stone-throwing protesters, a health ministry official said.
Police backed by armoured vehicles fired tear gas and shots after clashes in the square to scatter protesters who had gathered to mark the anniversary of deadly 2011 demonstrations.
One man was killed when he was struck by birdshot during the clashes, head of emergency services Ahmed al-Ansary told AFP. It was not immediately clear if he was a protester.
The crowds were marking the anniversary of 2011 protests against the military, which took power between president Hosni Mubarak's overthrow and his now deposed successor Mohamed Morsi's election in June 2012.
Egypt is divided between Morsi's supporters and those of the military that overthrew him, but Tuesday's protesters accused both sides of betraying the goals of a 2011 uprising that ousted president Hosni Mubarak.
The clashes had erupted near the Arab League's headquarters at the corner of the iconic square, where millions had rallied to pressure Mubarak and more than two years later Morsi to resign.
Ansari said 16 people were injured in the violence, including a man with a birdshot wound to the eye.
The protesters covered their faces to block the tear gas.
"I am here to retaliate for my friends killed in Mohamed Mahmud. No one has brought them their rights," said one young protester who gave his name as Mohamed.
In 2011, at least 43 protesters were killed over several days of clashes with police in the Mohamed Mahmud street clashes just off Tahrir Square.
The November 19 clashes were the first serious revolt faced by the military junta that had taken charge after Mubarak's resignation in February 2011.
The interior ministry said in a statement it arrested 14 "rioters", including one in the possession of home made shotgun, and accused the protesters of trying to storm the Arab League's headquarters.
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The military handed power to Morsi in June 2012, after he won the country's first free election, but ousted him a year later following mass protests demanding his resignation.
Morsi's ouster ushered in a massive crackdown on his Islamist followers that killed more than 1,000 in clashes. Thousands have been arrested.
Tuesday's clashes, however, took place between protesters who oppose both Morsi and the military appointed interim government.
Some of the protesters had been outraged by a monument inaugurated in the square on the eve of the Mohamed Mahmud anniversary.
By Tuesday, protesters had defaced the monument to those killed in the mass protests that helped unseat two presidents in less than three years.
Protesters accused the government and police of revising the history of the Mohamed Mahmud carnage amid a wave of pro-military nationalism following Morsi's overthrow.
"Celebrating in praise of the army is a provocation. We are here today to mourn the martyrs," said Magda al-Masrya, 50, as she took part in a protest in the square early on Tuesday.
Another protester, Reni Rafat, said: "What we need is trials of those responsible (for the deaths in November 2011) and not celebrations".
Mahmoud Hisham, a 21-year-old student, said: "The revolution is still not over.
"In three years we had three systems and three traitors -- Mubarak, the military and the Brotherhood."
Neither the Brotherhood nor the Tamarod movement which organised the mass protests that led up to Morsi's overthrow had called for Tuesday's rival demonstrations.