United Nations Secretary-General Ban Ki-moon has condemned the killing of dozens of people at a mass protest site in Cairo and called for an independent investigation into the incident.

On Monday, 51 people, mostly supporters of deposed Egyptian President Mohamed Morsi, were killed in clashes with the security forces outside the Republican Guard barracks in Cairo.

Ban's spokesman Martin Nesirky has said the UN chief was "deeply disturbed" by the killings, which have been described by Morsi's supporters as a "massacre."

"The Secretary-General condemns these killings and calls for them to be thoroughly investigated by independent and competent national bodies, and those responsible need to be brought to justice," Nesirky said.


Ban "calls on all Egyptians to be mindful of the precarious path the country is now on and to do everything possible to avoid further escalation," Nesirky added.

Ban urged all sides in the violence to exercise "maximum restraint."

"Protests must remain peaceful and the security forces must abide strictly by international standards," Nesirky added.

Ban called on Egyptians and political parties "to work constructively to forge a consensus on the way forward through peaceful means."

"The United Nations stands ready to assist as necessary," Nesirky added.

Egypt has been the scene of rival rallies and clashes between thousands of supporters and opponents of the ousted president as political turmoil escalates in the North African country.

Morsi was unseated on July 3, and the Chief Justice of Egypt’s Supreme Constitutional Court, Adly Mansour, was sworn in as interim president of Egypt on July 4.

Morsi is reportedly being held “preventively” by the military. Senior army officials say he might face formal charges over accusations made by his opponents.

Several arrest warrants have been issued for the members of Muslim Brotherhood. Egyptian troops and security forces have recently expanded their roundup of top political figures from Muslim Brotherhood that had fielded Morsi for office.