GENEVA — A UN committee on child rights criticized the United States on Friday for filing war crimes charges against Guantanamo Bay detainees like Canadian Omar Khadr who were picked up as minors.

The detainees were recruited to fight while they were children and should therefore be treated as victims rather than unlawful enemy combatants, the UN Committee on the Rights of the Child said.

U.S. officials say two men who were juveniles when they were first detained remain at the U.S.-run prison camp in Cuba. Khadr, now 21, and Mohammed Jawad, an Afghan who the military says is about 23, face charges of murder and attempted murder respectively for allegedly attacking U.S. troops in 2002.

"The committee is seriously concerned that children who were recruited or used in armed conflict ... have been charged with war crimes and subject to prosecution by military tribunals, without due account of their status as children," the committee said in a nine-page report.

U.S. officials in Geneva said they were unable to comment immediately on the report.

Last month, U.S. Deputy Assistant Secretary of Defence Sandra Hodgkinson said she would review how many juveniles were detained at Guantanamo after official documents cast doubt on the figures Washington has provided to the UN panel.

A lawyer who has reviewed the cases of several Guantanamo detainees says at least one inmate still being held at the prison was never recognized as a juvenile by the United States despite official records showing he was only 16 when he arrived there.

Clive Stafford-Smith, a lawyer with the British legal aid group Reprieve, says he has evidence that Muhammed Al-Qarani, a citizen of Chad, may have been as young as 14 when he was first picked up at a mosque in Pakistan in October 2001.

Rights groups say it is important for the U.S. military to know the real age of those it detains because juveniles are entitled to special protection.

The UN committee also expressed concern about the number of juveniles being held at U.S. detention facilities in Iraq and Afghanistan.

Minors should only be imprisoned as a last resort and must be treated with special care because of their vulnerability, it said.

The United States has said it has detained 2,500 juveniles since 2002, almost all in Iraq.

The juveniles - most of them between the ages of 16 and 17 - were detained for their own safety and all receive additional care including family visits, special legal representation and education, Hodgkinson told the committee at a one-day hearing in Geneva last month.

The UN committee was reviewing U.S. compliance with an international treaty on children in armed conflict that Washington has committed itself to.

In its concluding report, the committee urged the United States to raise the minimum age for military recruitment to 18 from 17.

It criticized the United States of failing to "prevent the deployment of volunteer recruits below the age of 18 years to Afghanistan and Iraq in 2003 and 2004." U.S. officials say the minors were never deployed on combat operations.

Pressure groups, including the American Civil Liberties Union and Human Rights Watch, claim that U.S. military recruiters regularly target persons younger than 17, in breach of the law.

The UN committee said it was concerned about the reports and recommended that U.S. legislation be changed to prevent recruiters from accessing school records against the wishes of parents or guardians.

"The committee has created a blueprint for change of U.S. practices on detention of suspected child soldiers abroad and military recruitment of children at home," said ACLU lawyer Jennifer Turner.

"The world will be watching whether the U.S. government swiftly implement's the UN's recommendations," she added.