The Guardian reports: The room is barely wider than the thin, dirty mattress that covers the floor. Behind a low concrete wall is a squat toilet, the stench from which has no escape in the windowless room. The rough concrete walls deter idle leaning; the constant overhead light inhibits sleep. The delivery of food through a low slit in the door is the only way of marking time, dividing day from night.

This is Cell 36, deep within Al Jalame prison in northern Israel. It is one of a handful of cells where Palestinian children are locked in solitary confinement for days or even weeks. One 16-year-old claimed that he had been kept in Cell 36 for 65 days.

The only escape is to the interrogation room where children are shackled, by hands and feet, to a chair while being questioned, sometimes for hours.

Most are accused of throwing stones at soldiers or settlers; some, of flinging molotov cocktails; a few, of more serious offences such as links to militant organisations or using weapons. They are also pumped for information about the activities and sympathies of their classmates, relatives and neighbours.

At the beginning, nearly all deny the accusations. Most say they are threatened; some report physical violence. Verbal abuse – “You’re a dog, a son of a whore” – is common. Many are exhausted from sleep deprivation. Day after day they are fettered to the chair, then returned to solitary confinement. In the end, many sign confessions that they later say were coerced.

These claims and descriptions come from affidavits given by minors to an international human rights organisation and from interviews conducted by the Guardian. Other cells in Al Jalame and Petah Tikva prisons are also used for solitary confinement, but Cell 36 is the one cited most often in these testimonies.

Between 500 and 700 Palestinian children are arrested by Israeli soldiers each year, mostly accused of throwing stones. Since 2008, Defence for Children International (DCI) has collected sworn testimonies from 426 minors detained in Israel’s military justice system.

Their statements show a pattern of night-time arrests, hands bound with plastic ties, blindfolding, physical and verbal abuse, and threats. About 9% of all those giving affidavits say they were kept in solitary confinement, although there has been a marked increase to 22% in the past six months.

Few parents are told where their children have been taken. Minors are rarely questioned in the presence of a parent, and rarely see a lawyer before or during initial interrogation. Most are detained inside Israel, making family visits very difficult.

Human rights organisations say these patterns of treatment – which are corroborated by a separate study, No Minor Matter, conducted by an Israeli group, B’Tselem – violate the international convention on the rights of the child, which Israel has ratified, and the fourth Geneva convention.