Updated

Israel must reform its system of military detention for Palestinian minors, a U.N. report said Wednesday, saying an in-depth study showed it systematically and gravely violated their rights.

The United Nations Children's Fund report was based on interviews with 400 children and minors arrested, detained and jailed in Israel's military court system as well as meetings with lawyers and Israeli officials.

"Ill-treatment of Palestinian children in the Israeli military detention system appears to be widespread, systematic and institutionalized," said the report, issued by U.N. officials in Jerusalem. They urged Israel not to blindfold minors or hold them in solitary confinement, and to allow a lawyer or family member to be present during interrogations.

The Foreign Ministry said Israel would cooperate with the U.N. body, and the military was already making changes.

"Israel will study the conclusions and will work to implement them through ongoing cooperation with UNICEF, whose work we value and respect," spokesman Yigal Palmor said in a statement.

An official from Israel's military prosecutor's office said most of the minors detained were above 16 years old. He said some were manipulated by militant groups into carrying out attacks. Most notably, a 17-year-old was one of the perpetrators of a stabbing attack in March 2011 that killed an entire family in a West Bank settlement. He spoke on condition of anonymity in line with military protocol.

Most children and minors — some 60 percent of those UNICEF interviewed — are ultimately charged with throwing rocks at soldiers or passing cars.

Rights activists have said Israel's military and police appear to use harsh tactics to deter the youths from throwing rocks again and to extract information about adult activists.

The UNICEF report said over two-thirds of all children interviewed were arrested in nighttime military operations. It said shouting soldiers often burst into homes, taking children and minors at gunpoint. Parents were not allowed to accompany them.

The alleged abuses also included interrogations without lawyers while minors were shackled, and threats of harm to the youths and their relatives. They said minors were often handcuffed and blindfolded while being transported from place to place.

Most minors were typically charged with crimes gleaned from confessions obtained during those interrogations, the report said. Children and minors were also made to sign confessions typed in Hebrew, a language most Palestinian minors don't read.

The report noted that recording interrogations would help ascertain if minors were exaggerating the trauma they claim to have suffered.

The U.N. organization reported that the Israeli military said it had reduced the maximum amount of time that a minor could be held before seeing a judge. By April, military authorities will set it to within 48 hours, the report said.

Israeli police now must also tell parents if their children have been arrested, and to inform children they have the right to consult a lawyer. UNICEF said the changes were not specific enough.

The report's authors said statistics at the end of January showed 233 males under 18 were being held in military prisons, 31 of them under 16. They estimated 700 boys and youths are detained each year.