From north to south, Iraqis have detailed abuse at US-run detention centres as military officials insist gruesome deeds at Abu Ghraib jail were the work of a few and not an indictment of the entire system.
But human rights campaigners say torture is endemic at camps across the country, while others lambast the US military for continuing to deny all but the International Committee of the Red Cross access to security detainees.
Qusay Mehawish, 23,said that he was held for five months at various prisons, including the infamous Abu Ghraib, because the Americans were hunting down his father, a former army general under deposed leader Saddam Hussein.
Arrested in October, he said he was abused during a two-hour interrogation at Camp Tiger, near the Iraqi-Syrian border.
"They hit me with a truncheon, beating me on the ribs so as not to leave any marks. Once, they electrocuted me in the nape of the neck. I had to sit on my knees. They beat me and I couldn't move," he said.
"When I fell, a soldier put a gun to my head. He told me he had come to kill me and pulled the trigger, but it wasn't loaded."
Ten days later, he was taken to Camp Bagdadi, in Al-Anbar province.
"The interrogator ... put me in a sleeping bag and coiled a long belt around my body. Then he put my head in a plastic bag and pulled it tight. I was suffocating, I thought I was going to die," he added.
Najm Majid, a shopkeeper in his 50s, was jailed for six months at Abu Ghraib on suspicion of belonging to an Islamist group, before being released in January.
"They beat and spat on me. They stuck my arms out in the air and burnt me with cigarettes. When I said I was tired, they hit me. They hooked up electric wires to my arms and feet, just to scare me," he said.
Khairallah Wali, a 65-year-old shopkeeper, showed a medical certificate saying he had two broken ribs, following his 33-day ordeal in Um Qasr in spring 2003.
Omar Motaleb, a 19-year-old student, was held for four months last year on charges of selling weapons and belonging to the radical Ansar al-Islam group, which is believed to have ties to Osama bin Laden's Al-Qaeda terror network.
He showed a medical certificate dated October 28, attesting to damaged knees and memory loss after he was subjected to "physical and psychological torture".
Last week, Suhaib al-Baz, a 24-year-old cameraman working for Dubai-based Al-Jazeera television, said he was beaten for three days at a military base near Samara, north of Baghdad, when he was arrested in November.
The first three witnesses spoke on Sunday at a conference organised by the International Occupation Watch Center and the Iraqi Institution for Human Rights that slammed US claims that torture was not a systematic practice.
"It is evident that torture is systemised and deliberate in all the detention camps all over Iraq," the non-governmental organisations (NGOs) said in a statement.
Cases of maltreatment include "kicking, punching, beating, electric shocks, dog biting, solitary confinement or putting the detainees in animal cages," it added.
In Geneva on Saturday, the Red Cross said systematic abuse in Iraq's US-run prisons amounted to torture, adding that it first raised concerns with the United States more than a year ago.
Seven US guards have been charged with criminal offences in relation to the abuse of prisoners at Abu Ghraib.
Human Rights Watch (HRW), which says it has been denied access of US-run jails in Iraq, said scores of former detainees had informed the New York-based group of mistreatment at the hands of the US-led coalition.
HRW representative in Iraq, Hania Mufti, said complaints by ordinary criminals included violence and manhandling, sleep deprivation, lack of food and occasional beating.
She echoed calls for an immediate investigation into claims of abuse and pressed the US military to allow NGOs into detention facilities in the wake of the revelations at Abu Ghraib that have shocked the world.