Zeid Raad Al-Hussein also criticised "the lack of accountability for human rights violations committed by security forces."
Referring to violence that took place over the past week, leaving five killed including two members of the security forces, the statement demanded Egyptian authorities ensure security forces do not resort to excessive use of force and demanded that protesters exercise their right to assembly in a peaceful manner.
Two protesters were killed in clashes with security forces on Saturday after charges against former president Hosni Mubarak were dropped. Two police officers were shot dead on 28 November after a Salafist group called for protests to "restore Egypt's Islamic identity."
The UN statement also condemned the sentencing of 78 minors to between two and five years for protesting. It urged the government to "immediately release all those who have been detained for the legitimate exercise of their rights to peaceful assembly, and to freedom of association and expression."
It demanded that the government re-examine the law defining an individual or a group a "terrorist entity" to ensure it meets human rights norms and standards. It further slammed the military trials of civilians, referring to 16 cases that followed a decision by President Abdel-Fattah El-Sisi to allow the military to protect “critical and sensitive facilities.”
Referring to a recent report issued by a fact-finding committee on the violence that followed the ouster of Islamist president Mohamed Morsi last year, the UN commissioner urged Egypt "to ensure that all those who are responsible for human rights violations, up to the highest levels, face justice in line with international standards of fair trial and due process."
Hundreds were killed and thousands injured in August of last year when security forces cracked down on sit-ins supporting Morsi.
Egypt has been witnessing an escalation of violence since Morsi's ouster. Security forces frequently clash with pro-Morsi protesters leaving many dead and injured. Meanwhile, Islamic militants have stepped up attacks against security forces leaving over 500 killed over the last year.
The UN had issued an outcome report following Egypt's Universal Periodic Review last month at its headquarters in Geneva. The report included 300 recommendations mainly centred on three controversial issues: a law regulating NGOs, capital punishment and another putting restrictions on protesting and freedom of expression.
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