London, Asharq Al-Awsat—More than 100 people have been reported killed by security officials in Egypt in what represents the worst state-led massacre since former president Hosni Mubarak’s ouster.

The violence took place in the early hours of Saturday morning at a sit-in at Raaba Al-Adawiya square in eastern Cairo, where supporters of recently ousted president Mohamed Mursi supporters have been camped out since July 3.

Egypt’s health ministry reported on Saturday that 38 people were killed, while the Muslim Brotherhood claimed that at least 139 people were killed and 4,500 others wounded in the attack.

The Muslim Brotherhood issued a statement on its official website on Saturday reporting that the violence began after security forces fired tear gas to disperse crowds at approximately 2 a.m. Following this, live ammunition was reportedly fired at the pro-Mursi protesters.

Initial reports indicate that the violence erupted after some Mursi supporters attempted to block a main road in the area overnight, forcing the military to respond.

The Brotherhood statement quoted Hisham Ibrahim, the field hospital director at Rabaa Al-Adawiya, as saying that most of those injured or killed were shot in the head, neck and chest by snipers.

For his part, Muslim Brotherhood spokesman Gehad El-Haddad said: “They are not shooting to wound; they are shooting to kill,” adding, “The bullet wounds are in the head and chest.”

However, Egyptian state news agency MENA quoted a security official as saying that no live ammunition had been used by the security forces on the ground.

The official claimed that the security forces had been trying to stop fighting between rival sides. He added that eight security officials had been injured in the violence

The violence took place after Egyptian interior minister Mohamed Ibrahim took the decision to end the weeks-long pro-Mursi sit-in outside the Rabaa Al-Adawiya mosque in eastern Cairo. Ibrahim said he took this decision after local residents complained about the continued presence of the Islamist demonstrators.

Ibrahim said that the Rabaa Al-Adawiya protests would be “brought to an end soon and in a legal manner,” with an order from the public prosecutor. It is not yet known whether Saturday’s violence was part of a sanctioned attempt to oust the pro-Mursi supporters from Rabaa Al-Adawiya square.

There were also clashes in the northern city of Alexandria, where reports indicate that at least 10 people were killed in violence between supports and opponents of the deposed president.

The latest bloodshed took place the day after supporters and opponents of deposed Islamist president Mohamed Mursi staged rival rallies across the country. Hundreds of thousands of Egyptians took to the streets in Egypt on Friday, exposing the deep state of polarization in the country.

Egyptian army chief Gen. Abdel-Fattah El-Sisi had initially called for a mass demonstration on Friday in support of the military and against “terrorism” and “violence,” while the Muslim Brotherhood had called for a counter demonstration against the “bloody military coup,” calling for Mursi’s reinstatement.

More than 250 people have been killed in Egypt in clashes and violence following Mursi’s ouster.