At least 120 supporters of deposed Islamist President Mohammed Morsi were killed on Saturday and hundreds injured when Egyptian security forces opened fire on protesters demanding his reinstatement, according to the Muslim Brotherhood.
Brotherhood officials said the security forces started firing shortly before pre-dawn prayers on protesters staging a sit-in here in support of Morsi, Egypt's first democratically elected president who was toppled by the military on July 3.
The Islamist group, which 61-year-old Morsi formerly headed, insisted that 75 of its supporters were killed and the figures are expected to rise as hundreds more were injured.
However, the Heath Ministry published a conflicting death toll, putting the figure at 19.
Nine people, including a 14-year-old boy, were killed in clashes in Egypt's second biggest city Alexandria yesterday, while at least 10 others died in Cairo today, the ministry said. Hundreds were also wounded nationwide, including at least seven policemen, health ministry officials said.
A doctor at a field hospital close to the protest at the Rabaa al-Adawiya mosque told the BBC that more than 1,000 people had also been injured.
A security source told state-run news agency MENA that 53 Brotherhood members were arrested for wielding arms.
Morsi, who is facing several criminal charges, was last seen in public on June 26 and has been detained along with senior aides of his Muslim Brotherhood party.
His overthrow after massive nationwide protests demanding his resignation plunged the most populous Arab country into turmoil, with Islamist supporters of Morsi organising rallies demanding his reinstatement.
Both pro- and anti-Morsi supporters had been holding huge protests overnight in the capital, with some supporting army and others angrily demanding his return to power.
Earlier, army chief Abdel Fattah El-Sisi had asked people to come on street to give him a mandate to confront "violence and terrorism".
Clashes also broke out in Upper Egypt's Luxor and Mahalah, located in the Delta governorate of Gharbiya.
In the Nile Delta city of Gharbiya, 10 people – including a police officer – were injured in clashes between loyalists and opponents of Morsi yesterday.
Meanwhile, clashes were ongoing in Sinai between pro- Morsi militant groups and the forces. Dozens have been killed in the restive peninsula since the beginning of the month.
According to Ahram Online, a number of high-ranking police officers joined the pro-military protesters in iconic Tahrir Square, the epicentre of anti-Mubarak uprising.
The officers were welcomed with cheers and chants of "the army, the police and the people are one hand."
Protesters held posters of army chief El-Sisi and pictures showing the Islamic crescent and the Christian cross as a symbol of national unity.
"It's a wonderful day. We lost a year of Egypt under Morsi who only brought us injustice; he destroyed tourism, the media, and the economy," said protester Khaled Mostafa, an employee in the justice ministry.
Tahrir and Ittihadeya palace, which is located in Cairo's Heliopolis district, were filled with demonstrators who supported the army. Dozens of police and military armoured vehicles were stationed around Tahrir Square and Ittihadeya as hundreds of thousands turned up.
An Egyptian court yesterday ordered that Morsi be detained for 15 days pending investigations for allegedly collaborating with the Palestinian militant group Hamas, an offshoot of the Brotherhood, escaping from Wadi El-Natroun Prison and destroying prison records during the 2011 uprising.
The area surrounding Rabaa Al-Adawiya Mosque, which has been the venue of the pro-Morsi sit-in since June 28 in Cairo's populous Nasr City, has seen a high turnout of people.
The atmosphere was relatively calm until the early hours today when at least 10 Morsi supporters were killed after clashes with security forces, according to Omar Amer, a doctor at the sit-in makeshift hospital.
Some 500 were also injured as violence erupted near the Unknown Soldier Memorial, located nearly one km away from Rabaa Al-Adawyia, according to Amer.
State news agency MENA reported that police forces led a crackdown on pro-Morsi protesters for seeking to block the nearby Six of October Bridge.
The Brotherhood maintains that the military-backed ouster of Morsi was an illegitimate coup d'etat, while army says it responded to the will of the people after millions thronged to the streets demanding an end to Morsi's rule.