United Nations human rights chief Navi Pillay said on Monday that Egypt's death penalty convictions and mass trials are "obscene and a complete travesty of justice".

In a statement, Pillay said that Egypt should release three al-Jazeera reporters jailed for seven years earlier in the day after being convicted of helping a "terrorist organisation", and she accused Egypt of "crushing" the media.

Those verdicts and the death sentences confirmed on Saturday for 183 Muslim Brotherhood members and supporters are the latest in a string of prosecutions "rife with procedural irregularities and in breach of international human rights law", she said.