UN Secretary-General Ban Ki-Moon condemns the killings at Egypt's Republican Guard in Cairo and asks that those responsible be brought to justice.
Ki-Moon is "deeply disturbed" by the death of over 50 people when supporters of the deposed president Mohamed Morsi clashed with the Armed Forces, said the secretary-general's spokesperson in a statement.
"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," the statement reads.
Ki-Moon extended his condolences to the victims' families and called upon all sides to exercise "maximum restraint."
The secretary-general also said that all Egyptians political parties need "to work constructively to forge a consensus on the way forward through peaceful means."
He noted that for success "all parties must be included" adding that the UN can offer assistance if needed.
Fifty-one people were killed and at least 435 were injured as Morsi's supporters – largely from the Muslim Brotherhood – clashed with the Armed Forces at the Republican Guard in Cairo in the early hours of Monday.
The Egyptian army said one officer died and 42 soldiers were injured, including eight in critical condition.
Former president Morsi was deposed by Egypt's Armed Forces on Wednesday following massive nationwide protests calling for his ouster. Judge Adly Mansour, the head of the High Constitutional Court, was sworn in as the country's interim president on Thursday.