The hanging of up to 20 people in Iran this week follows serious doubts about the fairness of their trials and respect for due process, leading to a "grave injustice", the United Nations' top human rights official said on Friday.
Zeid Ra'ad Al Hussein said the men had been executed for "purported terrorism-related offences" and that reports suggested most if not all were from a minority group - Sunnis from the Kurdish community.
"The application of overly broad and vague criminal charges, coupled with a disdain for the rights of the accused to due process and a fair trial have in these cases led to a grave injustice," Zeid said in a statement.