Ali Mohammed al-Nimr, who was 17 years old when he was arrested in February 2012 for joining anti-government protests and allegedly carrying a firearm in Saudi Arabia, is set to be executed by crucifixion, which involves crucifying the body to a pole with nails.

Ali's clemency appeals have been rejected, and he is likely to be executed in a few days despite international outrage.

While Ali was held in a juvenile offenders' facility, human rights organisations claimed that he was tortured into confessing and was also denied access to lawyers. 

According to Reprieve, a legal organisation that works for human rights of prisoners,  Ali's final appeal for clemency was secretly rejected last week. "No one should have to go through the ordeal Ali has suffered – torture, forced confession and an unfair, secret trial process, resulting in a sentence of death by crucifixion. But worse still, Ali was a vulnerable child when he was arrested and this ordeal began," Maya Foa, director of the death penalty team at Reprieve, said in a statement on the website

Ali's death sentence is being seen in the context of his relation to Shia cleric Sheikh Nimr al-Nimr, who was also sentenced to death for promoting "foreign meddling" in Saudi Arabia. Sheikh Nimr, Alis uncle, was arrested two years ago in Saudi Arabia's Shia-dominated Eastern Province.

Human rights activists are now seeking global intervention to stop Ali's execution.

"His execution – based apparently on the authorities' dislike for his uncle, and his involvement in anti-government protests – would violate international law and the most basic standards of decency. It must be stopped," Foa wrote.

"Unfair trials of Shia citizens amount to no more than a legal veneer for State repression of their demands to end long-term discrimination. The authorities should not compound their repression by killing a child offender," Joe Stark, deputy Middle East director for Human Rights Watch said on the website. 

Saudi Arabia is known to carry out the most number of executions in the world along with China and Iran, and has already executed more than 175 people in the past year after unfair trials, Amnesty International had reportedly said last month. 

In 2015, Saudi Arabia executed at least 132 people till September at a rate of nearly one execution every second day.