A U.N. human rights body has expressed concerns about a recent spike of executions in Egypt, following several death sentences handed down amid allegations of the use of torture to extract confessions.

Rupert Colville, the spokesman for the U.N. Human Rights Office, told reporters in Geneva on Friday that Egyptian authorities should take all measures needed to guarantee due process and investigate allegations of torture.

A total of 15 people were executed this month, including nine suspected Islamists.

The nine were found guilty of taking part in the 2015 bombing that killed Hisham Barakat. It was the first assassination of a senior official in Egypt in a quarter century.

Colville said that during their trial, the judges ignored accounts of torture to extract confessions.