Washington has rebuked UN human rights commissioner Louise Arbour for criticising its anti-terror tactics as the alleged secret jails row goes on.
Ms Arbour said reports the US was using secret overseas sites to interrogate suspects harmed its moral authority and she wanted to inspect any such centres.
The US said it was inappropriate and illegitimate for her to question US conduct on the basis of media reports.
The issue is dogging a European tour by US Secretary of State Condoleezza Rice.
Lots of human rights... can be set aside temporarily... but not the right to life and not the protection against torture
UN High Commissioner for Human Rights
She will meet Nato foreign ministers on Thursday for formal talks but at a dinner on Wednesday the jails allegation reportedly already surfaced.
"There were a number of frank interventions, always respectful of Condoleezza Rice as a person," a source briefed on the dinner was quoted by Reuters news agency as saying.
On Wednesday, Ms Rice said American interrogators were bound by an international convention banning the use of torture, regardless of whether they were working in the US or abroad.
Ms Arbour, a former Canadian Supreme Court justice, told reporters in New York on Wednesday that the global ban on torture was becoming a casualty of the US-led "war on terror".
She singled out the reported US policies of sending terror suspects to other countries and holding prisoners in secret detention.
"Two phenomena today are having an acutely corrosive effect on the global ban on torture and cruel, inhuman or degrading treatment," she said.
"There are lots of human rights that can be set aside temporarily in cases of emergencies, lots of them, but not the right to life and not the protection against torture," she added.
The UN human rights commissioner said the theme of Saturday's annual commemoration of the UN's adoption of the Universal Declaration of Human Rights in 1948 would be "terrorists and torturers".
She added that the US had played an important leadership role in civil and political rights but that there was now a perception they had withdrawn from the commitment to such liberties, which made it harder for the US to exercise moral leadership.
America's ambassador to the UN, John Bolton, said Ms Rice had already addressed the issue and he roundly criticised Ms Arbour.
It was, he said, "inappropriate and illegitimate for an international civil servant to second-guess the conduct that we're engaged in [in] the war on terror, with nothing more as evidence than what she reads in the newspapers".