UN rights chief Navi Pillay on Wednesday urged the Gaza Strip's Islamist rulers Hamas to halt a string of executions planned after the end of the Muslim Eid al-Fitr holiday.
"I am deeply concerned at the possibility that executions might be carried out over the course of the next weeks in Gaza and urgently appeal to the de facto authorities there not to implement any death sentences," Pillay said in a statement.
Eid al-Fitr, which marks the close of the Muslim fasting month of Ramadan, ended last Sunday.
During Ramadan itself, Hamas authorities had said that executions would take place after the holiday but have given no specific date.
Pillay described the judicial process in Gaza as deeply flawed.
"I am concerned about the process by which death sentences are imposed by military and civilian courts in the Gaza Strip," she said.
"Serious concerns have also been raised about ill-treatment and torture during interrogations of persons later sentenced to death."
According to Amnesty International, those sentenced to death include a 27-year-old who confessed under torture to the rape and murder of a six-year-old boy, committed when he was under 18.
Another man on death row, aged 23, was sentenced for "collaboration" with Israel, Amnesty said.
Pillay said international human rights law requires rigorous fair trial standards in cases where death sentences are applied.
"One absolute requirement is that the death penalty can only be imposed after a fair trial. This is currently not possible in Gaza, neither legally nor practically," she said.
Under Palestinian law, collaboration with Israel, murder and drug trafficking are all capital offences.