Police fired tear gas as clashes erupted in Cairo after Friday prayers when supporters of Mohamed Morsi protested ahead of a new court appearance by the deposed Islamist president.
Clashes took place in the districts of Nasr City, the upscale southern suburb of Maadi and in Giza, AFP correspondents and security officials said.
In Giza, protesters torched a police vehicle using petrol bombs, a security official said. State media said residents extinguished the fire.
In Maadi, police fired tear gas near a military hospital as protesters threw fireworks at them, an AFP reporter said.
He said protesters clashed with the police on a road along the Nile river and also inside the suburb.
The surface was littered with rocks and burning wood as police vehicles sped along the road to disperse the protesters.
However, the demonstrators regrouped in a side street, facing off with riot police and chanting "They are the thugs!"
Some protesters threw stones, the reporter added.
The stand-off ended as police fired shotguns at protesters and chased them, one officer shouting" "Make them run like chickens!"
In an eastern neighbourhood of Cairo, police also used tear gas against thousands of Morsi supporters who burnt tyres and threw fireworks at security forces, another AFP correspondent said.
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Gunshots were also heard.
Protesters chanted "Down with military rule" and slogans against army chief Abdel Fattah al-Sissi, who led Morsi's ouster in July.
Cairo's main squares were sealed off by security forces using barbed wire and military vehicles.
They included the iconic Tahrir Square and Rabaa al-Adawiya and Nahda squares -- the sites of a bloody crackdown on Morsi's supporters in August.
Medics said two people were wounded by gunshots in Morsi-related clashes in the Suez Canal city of Ismailiya.
Since the Islamist president's ouster, his supporters have staged near-daily protests calling for his reinstatement, particularly after Friday prayers.
But their numbers have dwindled amid a violent government crackdown.
Friday's protests come as a pro-Morsi Islamist coalition spearheading the protest movement called for demonstrations ahead of the resumption of his trial on Wednesday.
Morsi is being tried on charges of inciting the killings of protesters during his presidency.
He will also stand trial on January 28 over a jailbreak during the 2011 popular uprising that toppled long-time ruler Hosni Mubarak.
A date for him to be tried on espionage charges has yet to be fixed.
Egypt's military-installed government declared Morsi's Muslim Brotherhood a "terrorist organisation" last month after accusing it of a suicide car bombing at a police headquarters that killed 15 people.
The Brotherhood denied the accusation, and an Al-Qaeda-inspired group claimed responsibility for the bombing.