UNITED NATIONS - A group of United Nations human rights experts have called on the Bangladesh government to annul the death sentence against opposition Jamaat-e-Islami leader Mir Quasem Ali, and “re-try him in compliance with international standards”.

“International law, accepted as binding by Bangladesh, provides that capital punishment may only be imposed following trials that comply with the most stringent requirements of fair trial and due process, or could otherwise be considered an arbitrary execution,” they said in a statement issued Wednesday by the Office of the United Nations High Commissioner for Human Rights (OHCHR).

He was sentenced to death in 2014 by the Bangladesh International Crimes Tribunal (ICT) for crimes against humanity committed during the 1971 Bangladesh Independence War . The decision was confirmed by the Appellate Division of the Supreme Court on 8 March 2016.

“The death penalty is the most severe form of punishment,” the experts stressed. “In light of its irreversibility, every measure must be taken to ensure that all the defendants before the International Crimes Tribunal, including the Appellate Division, have received a fair trial.”

In their statement, the experts recalled that the Working Group on Arbitrary Detention found in 2012 that Quasem Ali's deprivation of liberty was arbitrary and in breach of articles 9 of the  Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights .

“We regret the Government's non-compliance with the expert group's recommendations to remedy the situation of Quasem Ali, and call upon the Bangladeshi authorities to respect their international obligations,” they added.

The UN human rights experts also expressed alarm at reports that Quasem Ali's son and part of his legal defence team, Mir Ahmed Bin Quasem, was abducted from his home on 9 August by Bangladeshi security forces, two weeks before his father review hearing.

“We understand that no information has been given on where he is being held, by whom or under what suspicion or charge. We urge the authorities to immediately disclose the whereabouts of Mir Ahmed Bin Quasem,” they said.

The experts added that the UN human rights experts have on several occasions expressed alarm regarding serious violations of fair trial and due process guarantees in the judicial proceedings before the ICT that were reported to them.

The ICT is a special domestic court with the jurisdiction to try and punish any person accused of committing atrocities, including genocide, war crimes and crimes against humanity in the country. It has sentenced 17 individuals to death for crimes committed during the Independence war .

In the past three years, five of those convicted by the ICT have been executed.

The request was made on Tuesday as theSupreme Court prepares to review the final verdict on Wednesday.

The experts are: Agnes Callamard, new UN Special Rapporteur on extrajudicial, summary or arbitrary executions; Monica Pinto, UN Special Rapporteur on the independence of judges and lawyers; Juan E Mendez, UN Special Rapporteur on torture and other cruel, inhuman or degrading treatment or punishment; Setondji Roland Adjovi, current chairperson of the UN Working Group on Arbitrary Detention; and the UN Working Group on Enforced or Involuntary Disappearances.