Thousands of Morsi loyalists held a sit-in demonstration at Cairo's Rabaa al-Adawiya mosque on Saturday morning, waving Egyptian flags and carrying portraits of the deposed leader.
The gathering comes amid heightened political tensions in Egypt, following a day of rival rallies across the country – the largest since the formation of a new government this week – which turned violent in the Nile Delta city of Mansura.
"Three people were killed and seven others wounded by birdshot and stabbing attacks during clashes between Morsi supporters and his opponents," Adel Said, a hospital official in Mansura, told Agence France-Presse.
Health officials on Saturday confirmed the three killed were all women, and gave a toll of 34 people wounded in Mansura.
A pro-Morsi protester injured in the clashes said thousands of loyalists were marching through the city's narrow streets when "thugs" attacked them with guns, knives and rocks.
Friday's pro-Morsi protests, dubbed "Breaking the Coup" by the Muslim Brotherhood, came three days after interim president Adly Mansour swore in a new Cabinet, whose legitimacy has been categorically rejected by the Islamists.
Thousands of supporters of Morsi's overthrow by the military also descended on Cairo's Tahrir Square on Friday evening, setting off fireworks and chanting pro-army slogans in a carnival atmosphere.
On the eve of the demonstrations, Mansour pledged to rein in those who wanted to push Egypt "into the unknown" while the army warned it would decisively confront any violent protesters.
A vast crowd gathered at the Rabaa al-Adawiya mosque, where Morsi loyalists have camped out since the week before the military overthrew him on July 3.
About 10 000 protesters then set off in the direction of an elite military compound, scene of the deadliest violence since Morsi's overthrow, carrying pictures of the ousted president and chanting slogans.
But they were blocked by soldiers and armoured vehicles.
"Islamic, Islamic," they shouted, airing their hopes for an Islamic state.
"I believe Morsi will return as president, God willing. The people will win in the end," said protester Mohammed, a 45-year-old veterinarian.
The deposed Islamist president has been held in custody since his overthrow, while the authorities has also detained other senior Brotherhood leaders and frozen their assets, prompting international concerns.
UN rights chief Navi Pillay summoned the Egyptian ambassador in Geneva and requested information about those arrested in connection with the events since the July 3 coup, her spokesperson said on Friday.
Although mostly peaceful, the pro-Morsi protests have resulted in deadly clashes, with the unrest claiming more than 100 lives in all, according to an Agence France-Presse tally.
Olive branch to the Brotherhood
In the worst bloodshed, at least 53 people, mostly Morsi supporters, were killed outside the Cairo headquarters of the Republican Guard on July 8.
The Brotherhood accuses the army of committing a "massacre," while the military says it was responding to a "terrorist" attack.
The demonstrations by those celebrating Morsi's ouster have been far smaller since the mass rallies that swept the country in the days leading up to the coup.
In his speech, Mansour offered an olive branch to the Brotherhood, saying: "The framework of justice and reconciliation extends to all."
On the diplomatic front, Britain announced it was revoking export licences for equipment used by Egypt's military and police amid concerns it could be used against protesters.
The United States has refrained from saying Morsi was the victim of a coup, which would legally require Washington to freeze some $1.5-billion in US military and economic aid to Cairo. – AFP