The six men, who were convicted in 2015 of terrorism-related charges linked to the killing of a police officer, have all reported being tortured and forced to confess, the UN rights office said in a statement.
A group of UN human rights experts on Thursday demanded that Egypt halt the planned executions of six men sentenced to death on the basis of forced confessions.
The six men, who were convicted in 2015 of terrorism-related charges linked to the killing of a police officer a year earlier, saw their death sentences upheld by Egypt's highest criminal court on June 7.
The men – Basem Mohsen Elkhorieby, Khaled Askar, Mahmoud Mamhouh Wahba, Ibrahim Yahia Azab, Abd Elrahman Attia and Ahmed al Waleed al Shal – have all reported being tortured and forced to confess, the UN rights office said in a statement.
Three of the men were forced to confess on national television, it added.
"To proceed with the executions of the six men on the basis of these flawed trials would violate international human rights law and constitute arbitrary executions," the experts said.
"It is extremely worrying that while all six men recanted their forced confessions in court and indicated that they had been obtained under torture, these were still used as the basis for their convictions."
The experts also stressed that evidence used against the men, including testimonies from members of the state security forces, showed "major inconsistencies."
Some witness statements, for instance, did not match video footage of the alleged crime scene, they said.
The experts pointed out that capital punishment is only permitted under international law if there is "full respect for stringent due process guarantees."
"The government must halt these executions and ensure a retrial in compliance with international law and standards," they insisted.