The 20 men were executed for a series of crimes, including attacks on police stations and working against state security, Iran media reported on Thursday.

"These people had committed murder... killed women and children, caused destructions and acted against the security and killed Sunni religious leaders in some Kurdish regions," IRIB television quoted Prosecutor General Mohammad Javad Montazeri as saying.

All of the prisoners were hanged on Tuesday.

Tawhid and Jihad

On Wednesday, Iran's intelligence ministry issued a report detailing 24 armed attacks between 2009 and 2011. All of the attacks were apparently committed by a single group, called the "Tawhid (monotheism) and Jihad."

The group was responsible for 21 deaths in that time span, in addition to bombings and robberies, the ministry said. Most notably, the militia assassinated two Sunni religious leaders in Assembly of Experts, the powerful body of Islamic clerics in Shiite-dominated Iran.

The officials also said they identified 102 members of the Sunni extremist group and that a number of them died "in armed clashes with police forces."

"Some of those arrested were sentenced to death while some received prison terms," they added.

Ayatollah to be 'held accountable'

The Norway-based Iran Human Rights group decried the Tuesday executions, and called on international observers to condemn it.

"Many if not all of these prisoners were subjected to unfair trials and sentenced to death based on confessions extracted under torture," spokesman Mahmood Amiry-Moghaddam said.

"Their execution is a crime, and Iran's Supreme leader Ali Khamenei and the other leaders of the Islamic Republic must be held accountable for these crimes."

Prison or graveyeard

The wife of one of the prisoners told the activists that Iranian authorities called her ahead of the execution to come in for a final visit to her husband.

"More than 20 families were told to come to Rajai Shahr Prison, and we're currently on our way there," she said on Tuesday.

However, the families soon received another call telling them to go directly to a local cemetery where their relatives were to be buried.

Iran executed 977 people in 2015, according to Amnesty International, and 700 more prisoners have died since beginning of this year.

dj/kl (dpa, AFP, Reuters)