Saudis planning mass execution: Rights group

"National media outlets close to the Saudi Arabian authorities" reported the convicted persons would soon be put to death, said Amnesty International in a recent report.

Some of those to be put to death are supposedly al-Qaeda affiliates or charged with attempting to overthrow the government.

"Beheading or otherwise executing dozens of people in a single day would mark a dizzying descent to yet another outrageous low for Saudi Arabia, whose authorities have continued to show stone-faced cynicism and even open defiance when authorities and ordinary people around the world question their sordid record on the use of the death penalty," said Amnesty International's Deputy Director of the Middle East and North Africa James Lynch.

Five Shia Muslim activists are among those to be beheaded, three of whom are children. The families of all have requested clemency from Saudi Arabia's King Salman.

Among the juveniles is Ali Mohammed Baqir al-Nimr, the nephew of prominent Shia cleric Ayatollah Nimr Baqir al-Nimr, who was 17 when he was arrested in 2012. The UN and the European Parliament have previously asked Riyadh to halt Nimr's execution as international law prohibits the execution of people under the 18 years of age.

According to Amnesty, 151 people have been executed by Saudi Arabia since the beginning of the year. "Saudi Arabia's macabre spike in executions this year, coupled with the secretive and arbitrary nature of court decisions and executions in the kingdom, leave us no option but to take these latest warning signs very seriously," said Lynch.