A coalition of international human rights groups has released a report criticising the trial of 94 activists in the United Arab Emirates.
The report describes the proceedings as being in "flagrant disregard of fair trial guarantees".
It cites what it says is the failure by the judge to investigate "credible" allegations of torture of defendants.
The human rights groups also note that international observers were denied access to the trial.
The four human rights groups - The Gulf Centre for Human Rights, the International Federation for Human Rights, the Arab Network for Human Rights Information and the Cairo Institute for Human Rights Studies - released the report on Monday.
The coalition said there had been what it believed was a serious breach of the obligation to prevent pre-trial torture adding: "We further believe that the court, having heard the allegations of torture, failed to order any investigation of the allegations or to address them in any way."
However the UAE Attorney General Ali Salim al-Tenaji has insisted that the prisoners are being "dealt with according to the law".
The 94 activists, said to be members of an Islamist organisation, have gone on trial charged with plotting to overthrow the United Arab Emirates government.
The group - all Emiratis - was arrested in a series of raids last year. The detainees include two prominent human rights lawyers, as well as judges, teachers, and student leaders.
If convicted, the activists, including 13 women, face up to 15 years in jail, with no right of appeal.
The government alleges that they were part of a secret cell with links to the Muslim Brotherhood movement.
Most of those arrested belong to the conservative religious society al-Islah.
On Monday the UAE authorities arrested three men believed to be members of al-Islah, including one who had tweeted about the trial. n Emirati human rights activist, who asked not to be named told the BBC "the authorities want to make an example to others".
The trial of the 94 continues at the Federal Supreme Court in Abu Dhabi.