The prisoners recount being beaten until they urinated blood, given electric shocks, and confined in isolation without access to lawyers
Thrown into jail for their political or religious views, Vietnam's prisoners of conscience are routinely tortured, beaten and kept from their families, Amnesty International said in a report published Tuesday.
The rights group interviewed 18 prisoners of conscience who collectively spent over 77 years in prison for activism, questioning injustices in society or for their ethnicity and religious beliefs.
In the report, "Prisons within Prisons", those interviewed recount being beaten until they urinated blood, given electric shocks and confined in isolation without access to family members or a lawyer.
One former prisoner of conscience told Amnesty he was beaten unconscious and left in a cell for four days without food. When he asked for food, officers prepared a bowl of rice for the dogs outside his cell, and then gave him what was left.
"On one occasion, pens were placed between his fingers and his hands were twisted around, causing excruciating pain. On another, the legs of a table were placed on his toes and police put all their body weight on the table resulting in unbearable pain and causing his toes to bleed," read the report.
"When his interrogators began electrocuting him and told him that his entire family, including his wife and child, would be arrested if he did not confess, he finally relented and agreed to plead guilty to the charges against him."
The report accuses Vietnamese officials of using prisoners known as "antennae" who work with authorities and take part in torture and continue interrogations inside prison cells, in exchange for favourable treatment.
Amnesty said in the most extreme case it heard, a Hoa Hoa Buddhist, Mai Thi Dung, had to share cramped cells with a series of different women who would question her about her activism at night, after she had endured up to 10 hours of interrogation by authorities.
She was locked in a tiny room "with no open windows or ventilation shafts resulting in such bad ventilation that it was difficult to breathe."
On one occasion prison authorities "presented her with a document for her to sign which guaranteed her conditions of detention in which she could move and breathe easily in exchange for a confession. She declined."
Another prisoner said his "antennae" cellmate threatened to gouge his eyes out with a sharpened toothbrush handle unless he confessed to the charges against him.
A female land rights activist, Nguyen Thi Thuy Quynh, said when she was brought to trial 15 of her 17 defence witnesses were prevented from entering the courtroom.
At the end of the trial she heard an intercom announcement "calling the witnesses who had testified against her to collect the money they were promised to cover the costs of their travelling to the court to take part in the proceedings".
Vietnam, a one-party state, is regularly denounced by rights groups and Western governments for its intolerance of political dissent and systematic violations of freedom of religion.