Egyptian security forces Friday opened fire on a crowd of supporters of ousted President Mohamed Morsi in Cairo, killing three men, officials said.
The incident happened outside the officers' club of the Presidential Guard where Morsi is believed to be detained, the BBC reported.
Troops initially fired rounds into the air but then fired at the crowd, the BBC said. A man in his 30s was reported killed.
The Muslim Brotherhood called for the protest against the ouster of Morsi, Ahram Online reported.
Pro-Morsi marches also took place in Alexandria, Beheira and Minyain, among other cities.
Meanwhile, the African Union suspended Egypt's membership Friday and said it would work to help the country return to "constitutional order."
The organization posted on its Twitter page it was reacting to "the overthrow of the democratically elected Egyptian president," Voice of America reported.
The AU Peace and Security Council took the action during a meeting in Addis Ababa, Ethiopia.
The 54-nation bloc said it would it send a delegation to Egypt "to work toward restoring constitutional order."
Also Friday, Muslim Brotherhood lawyer Mustafa el-Demeiry told Ahram Online Mohamed Badie, the group's leader, learned a warrant was issued for his arrest and would surrender but wasn't sure to which authority.
Egypt's army said it would permit peaceful protests and Muslim Brotherhood supporters prepared to rally for the ousted Morsi.
"Peaceful protest and freedom of expression are rights guaranteed to everyone, which Egyptians have earned as one of the most important gains of their glorious revolution," the army said.
Demeiry told Ahram Online three Muslim Brotherhood leaders were in Tora Prison -- Saad el-Katatni, chairman of the brotherhood's Freedom and Justice Party, Mahdi Akef, the group's former leader, and Abdel Moneim Abdel-Maqsoud, a brotherhood lawyer arrested Friday after going to the prison to defend the two leaders.
Interim President Adly Mansour, the chief judge of Egypt's constitutional court, pledged to hold elections based on "the genuine people's will," the BBC reported.
Gehad al-Haddad, spokesman for the Muslim Brotherhood, of which Morsi is a member, said the organization would not work with the new regime.
"We are being headhunted all over the country," Haddad said. "We are holding a mass rally after Friday prayers to take all peaceful steps necessary to bring down this coup."
State prosecutors said Morsi, who was in military custody, would face an investigation starting next week into claims he had "insulted the presidency," the British newspaper The Guardian reported.
Morsi was ousted Wednesday after days of protests across the country that left at least 50 people dead. Demonstrators accused Morsi and the brotherhood of pursuing an Islamic agenda and not tackling the country's economic woes.
The army said it had to step in after Morsi "failed to meet the demands of the people."
Mohamed ElBaradei, an opposition leader who backed Morsi's removal, said the army's intervention was "a painful measure" but ultimately averted civil war.
"Mr. Morsi, unfortunately, undermined his own legitimacy," he told the BBC.
Mohamed Soudan, foreign relations secretary for the Muslim Brotherhood-affiliated Freedom and Justice Party, said the military's actions pushed Egypt "back to the dictatorship regime."
Islamic fringe groups threatened payback for Morsi's overthrow, CNN reported.
Police arrested four men Friday who allegedly planned a revenge attack, and confiscated arms and explosives, al-Ahram reported.