The United Nations' top human rights advocate, Navanethem Pillay, on Wednesday appealed to the Obama administration to release Guantanamo Bay inmates or try them in a court of law, and said officials who authorized the use of "torture" must be held accountable.

    In her most detailed statement on U.S. detention policy, the South African lawyer criticized President Obama's plan to hold some terrorism suspects in detention indefinitely without a trial. She also called for a probe of officials involved in the Bush administration's harsh interrogation program.

    "People who order or inflict torture cannot be exonerated, and the roles of certain lawyers, as well as doctors who have attended torture sessions, should also be scrutinized," Pillay, the U.N. high commissioner for human rights, said in a statement dedicated to victims of torture.

    Pillay praised the Obama administration for committing to ban many of the harshest interrogation techniques authorized by the Bush administration, including waterboarding, saying they "amount to torture." But she said it needs to go further by providing victims of U.S. abuses with an opportunity to rebuild their lives.

    "I believe we are finally starting to turn the page on this extremely unfortunate chapter of recent history, with counter-terrorism measures starting to move back in to line with international human rights standards," Pillay said. " . . . But there is still much to do before the Guantanamo chapter is truly brought to a close."

    The United States responded by highlighting the steps the administration has taken on human rights. "The Obama Administration has taken aggressive action on this issue from day one, upholding our nation's fundamental values while making the American people safer," Mark Kornblau, a spokesman for the U.S. mission to the United Nations, said in a statement. "The President banned the use of so-called enhanced interrogation techniques, initiated a review of all pending cases at Guantanamo, and ordered that facility closed within one year."

    Pillay's remarks represented the clearest challenge by the United Nations' high commissioner to Obama's decisions to limit investigation into past abuses and to continue to hold some detainees without trial. In May, Obama said some detainees deemed too dangerous to release might have to be held indefinitely.

    "There should be no half-measures, or new creative ways to treat people as criminals when they have not been found guilty of any crime," Pillay said. "Guantanamo showed that torture and unlawful forms of detention can all too easily creep back in to practice during times of stress, and there is still a long way to go before the moral high ground lost since 9/11 can be fully reclaimed."

    Pillay did not address the Obama administration's decision to use reformed military commissions to try terrorism suspects. Human rights groups have criticized the commissions, expressing particular concern that suspects could be convicted and put to death on the basis of evidence obtained under harsh interrogations.

    Pillay said that detainees who are not prosecuted, and who could face abuse if they are sent back to their own countries, "must be given a new home, where they can start to build a new life, in the United States or elsewhere. I welcome the fact that in recent weeks a number of countries have agreed to take in a few people in this position, and urge others to follow suit, including first and foremost the United States itself."

    This month, the Obama administration for the first time flew a Guantanamo detainee, Ahmed Ghailani, to the United States to face charges for his alleged role in the 1998 bombings of two U.S. embassies in East Africa. But an overwhelming majority of Republican and Democratic lawmakers have fiercely resisted allowing any more of the remaining 229 detainees at the U.S. military prison in Cuba into the United States.