A decision by US officials to livestream the execution of convicted killer Nidal Hasan would amount to torture, the UN said Friday.

US defence officials said US Army psychiatrist Hasan, who shot and killed 13 people at a military base in 2009, would face a firing squad and the execution would be broadcast live, adding that details would come later.

"The livestreaming of an execution is tantamount to a public execution and would breach the absolute prohibition of torture," the Office of the High Commissioner for Human Rights said in a message sent to AFP.

The UN body said it had made similar statements about public executions in Afghanistan and Iran, saying they "constitute a form of cruel, inhuman or degrading treatment or punishment". 

Hasan's execution will be the first by the US military since 1961, and the first it has carried out by firing squad since World War II.

According to rights group Amnesty International, at least 17 public executions are known to have been carried out in 2025 -- six in Afghanistan and 11 in Iran.

© Agence France-Presse