The study was conducted by the human rights group Amnesty International, which advocates for less restrictive placements or foster homes for children who are awaiting determination of their legal status.

"We found frequently instances of abuse such as solitary confinement for such offenses as poor hygiene or poor sportsmanship or misuse of grammar," said William F. Schulz, executive director of Amnesty International U.S.A.

"We found use of shackles and belly chains and leg irons on children as young as 7 when they appear in court," Mr. Schulz said. "What is most disturbing about this is it reflects a mentality that would punish those who have been seriously harmed already in their home countries rather than offering them protection and a quick adjudication of their claims."

Government officials said they welcomed the report and were reviewing the conditions at its centers. For decades, the federal immigration service was responsible for unaccompanied immigrant children. In March, the children were transferred to the care of the Department of Health and Human Services, a move hailed by advocates for immigrants.

Officials at the Department of Health and Human Services inherited the often-criticized detention system from the immigration service and said they were working hard to improve it. About 500 unaccompanied minors are currently being held while the government seeks to adjudicate their immigration claims.

"It's an important piece of information for us as we move forward in implementing this program," Wade Horn, the department's assistant secretary for children and families, said of the Amnesty report.

"We've been out visiting the various facilities we have contracts with to ensure that those facilities are in fact appropriate," Mr. Horn said in an interview. "What we've been doing is trying as best we can to put in place a system where the focus is on the individual needs of the child and making sure the placement is consistent with the needs and circumstances of that child."

The study found that nearly 50 percent of the detention facilities surveyed had improperly housed immigrant children in the same cells with juvenile offenders. Nearly 60 percent of the centers used solitary confinement to discipline children, even for minor infractions.

More than a dozen of the centers failed to provide lists of lawyers so that the children could be represented in court.

Mr. Schulz said he was encouraged by his talks with officials at the human services department and said they seemed committed to improving the system.

The New York Times, June 19, 2003