Cecile Pouilly, a spokeswoman for the U.N. High Commissioner for Human Rights, said the world body was alarmed by the escalation of violence tied to the political crisis in Egypt.
The Egyptian military last week declared an end to the presidency of Mohamed Morsi barely a year after he took office as the first democratically elected leader in Egyptian history. The United Nations said more than 30 people were killed in Friday violence and 51 more were reported dead following clashes in front of a military headquarters Monday in Cairo.
"We remind the Egyptian authorities that any incidents resulting in deaths and injuries require prompt, thorough and transparent investigation and those found to be guilty of wrong doing should be brought to justice," Pouilly said in a statement from Geneva.
Morsi, who hails from the conservative Muslim Brotherhood, was criticized for favoring Islamists and for not doing enough to address economic woes.
Interim authorities in Cairo announced plans to amend the constitution and hold swift parliamentary elections to reset the post-revolutionary political climate in Egypt. The Brotherhood rejected the proposal.
"We urge all parties to engage in a constructive dialogue and in a broad-based and inclusive process to move the country forward," Pouilly said.