One man was tortured and beheaded for sending messages from WhatsApp when he was only 16, it is claimed.
Abdulkarim al-Hawaj, 21, was sentenced as a "terrorist" to communicate with others about an anti-government protest in the repressive Arab state.
He was allegedly chained, beaten and electrocuted before "confessing" his crimes, according to the Reprieve human rights organization.
Amnesty International defined his trial as a farce by stating that he was denied adequate legal representation and forced to confess.
The organization added that he had been told that his family would be killed if he did not admit his guilt.
He was one of 37 men executed in Saudi Arabia on Tuesday, bringing the total number of executions in the country this year to 105.
At least one of the men executed last week was crucified, according to reports.
The state's state news agency said the men were convicted of terrorism charges, although Amnesty International claimed that 11 of them were convicted of espionage for Iran.
Mr. al-Hawaj, like most of the men executed last week, was a member of the Shiite minority in the Sunni-dominated country.
The Sun reported that the United Nations High Commissioner for Human Rights Michelle Bachelet said: "It is particularly aberrant that at least three of the victims are minors at the time of conviction."
Bachelet asked the Saudi regime to stop further capital punishment, including executions by the death trio Ali al-Nimr, Adawood al-Marhoon and Abdulla al-Zaher.
Iranian Foreign Minister Mohammad Javad Zarif rejected the United States for silence on the latest executions.
He said: "After winking at the dismemberment of a journalist (Jamal Khashoggi), not a whisper of the Trump administration when Saudi Arabia beheads 37 men in one day."
. (tagToTranslate) Saudi Arabia (t) Amnesty International (t) Terrorism (t) Human rights (t) Iran (t) death penalty