The rights experts renewed their call on Thursday for Guantanamo to be closed and criticised the administration of George Bush for a proposed law they said might permit torture in certain circumstances.
"We note with the greatest concern that the government has not taken any steps to close Guantanamo," the rights experts said in a joint statement read out by Algerian Leila Zerrougui, a specialist on arbitrary detention.
"Indeed, a new block has been built and is set to open this month."
The US responded by saying it would like to close Guantanamo eventually, but it said it needed to find alternative means of protection from suspected terrorists.
It criticised the allegations as poorly established, insisting detainees are treated humanely.
The rights experts were presenting their findings to the UN Human Rights Council. A summary of their report was released earlier this year. It demanded the United States close the detention facility and said it was effectively a torture camp where prisoners had no access to justice.
The US insists that the detainees
are treated humanely
Zerrougui told the council to take note of "serious human rights violations taking place in Guantanamo." She said the United States has not sought to end those violations.
The statement also criticised Bush's proposal on a new law to treat dangerous terrorism subjects, saying it failed to uphold the absolute prohibition on torture and "might permit abuses depending on the circumstances."
Zerrougui said the bill would ensure that detainees were still denied minimum standards for fair trials.
Warren W. Tichenor, the US ambassador to the UN in Geneva, criticised the experts for asserting "without real evidentiary support, conclusions they had clearly already reached."
Tichenor said the experts also misunderstood the law, arguing that a country's obligation to guarantee all people's civil and political rights does not apply outside of its borders.
"The Guantanamo facility is established under and governed by the law of armed conflict, or international humanitarian law," he said.
Many of the allegations in the report had been made before. However, this was the first UN-sanctioned inquiry into US practices at Guantanamo.