UN human rights chief Navi Pillay on Sunday urged Senegal to reconsider sending Chad's former dictator Hissene Habre back to his home country to face justice for alleged atrocities.
"I urge the government of Senegal to review its decision," Pillay said in a statement, adding guarantees should at the very least be obtained that Habre would not be subjected to torture or the death penalty and would get a fair trial.
Habre Habre ruled Chad from 1982 and fled to Senegal in 1990, when he was overthrown by incumbent President General Idriss Deby Itno.
A 1992 truth commission report in Chad said Habre had presided over 40,000 political murders and widespread torture.
In 2008, a court there sentenced him to death for crimes against humanity in a trial held in his absence.
The former dictator had spent two decades in exile in Senegal, which has announced it would sent him home on a private plane on Monday.
"As a party to the Convention Against Torture, Senegal may not extradite a person to a state where there are substantial grounds for believing he would be in danger of being subjected to torture," Pillay said.
"At the very least Senegal must obtain fair trial guarantees from the government of Chad before any extradition takes place."