The U.N. grilled the United States on its compliance with the global ban on torture Friday for the first time since Washington declared war on terrorists, rejecting U.S. refusals to discuss intelligence matters like alleged secret CIA prisons and flights transferring suspects for possible torture in other countries.

The U.N. Committee Against Torture, the global body's watchdog for a 22-year-old treaty forbidding prisoner abuse, asked U.S. officials about a series of issues ranging from Washington's interpretation of the absolute ban on torture to its interrogation methods in prisons such as Abu Ghraib, Iraq, and Guantanamo Bay, Cuba.

U.S. officials acknowledge mistakes had been made and that 29 detainees in American facilities in Iraq and Afghanistan had died of what appeared to be suspected abuse or other violations of U.S. law.

U.S. State Department lawyer John B. Bellinger III, who led the U.S. delegation at the hearing, defended Washington's commitment to its international obligations and read prepared answers to written questions submitted in advance from the committee in writing.

He said the delegation was unable to answer all questions because much of the information relates to intelligence activities.

But Andreas Mavrommatis, chairman of the committee, said he could understand that intelligence matters needed careful treatment, "but they are not excluded" from scrutiny.

"If during intelligence activities there is a violation of the convention, it's our duty to investigate them and your duty to answer," Mavrommatis said.

Bellinger's 25-member team for the hearings includes officials from the defense, justice and homeland security departments. A second session is planned for Monday, when U.S. officials will respond to the committee members' oral questions.

"While I am acutely aware of the innumerable allegations ... about various U.S. actions, I would ask you not to believe every allegation that you've heard. Allegations about U.S. military or intelligence activities have become so hyperbolic as to be absurd," Bellinger said.

U.S. Deputy Assistant Secretary of Defense Charles Stimson said a total of 120 detainees have died in Iraq and Afghanistan. No detainees died at Guantanamo Bay, he said. Most of the deaths resulted from natural causes, battlefield injuries or attacks by other detainees, he said.

In the cases of the 29 deaths from suspected abuse, Stimson said, "these alleged violations were properly investigated and appropriate action taken," he said.

The United States, like the 140 other nations that have signed the Convention Against Torture, must submit reports to the committee to show it is applying the rules.

The Geneva-based committee, a panel of 10 independent experts who meet twice a year, said the legal interpretation of torture in U.S. Department of Justice memorandums in 2002 and 2004 "seems to be much more restrictive than previous United Nations standards."

The committee is demanding the U.S. explain why it established secret prisons, what rules and methods of interrogation it employs, and whether U.S. President George W. Bush's administration assumes responsibility for alleged acts of torture committed by American agents outside U.S. territory.

U.S. Assistant Secretary of State for Human Rights Barry Lowenkron said the abusive acts against detainees at Iraq's Abu Ghraib prison "sickened the American people — just as they appalled people around the world. They were inexcusable, they were indefensible."

The U.S. conducted more than 600 criminal investigations into allegations of mistreatment and more than 250 people have been held accountable for abusing detainees, Lowenkron said. Investigations and charges are continuing, he said.

Criticism by the U.N. panel brings no penalties beyond international scrutiny. The committee is expected to issue conclusions when it concludes its session May 19.

Washington neither confirms nor denies allegations of secret prisons on grounds that it refuses to comment on intelligence matters.

But the committee cautioned that enforced disappearances of suspects "can be considered a form of torture" and asked for details on the U.S. policy of "Extraordinary Rendition," a euphemism for transporting suspects to third party countries where they could face torture.

U.S. officials have acknowledged flying up to 150 terror suspects from one country to another, but said they receive "diplomatic assurances" from authorities that torture won't be used on the detainees they receive.

"The United States has not transported anyone and will not transport anyone to a country where the United States believes he or she will be tortured," Bellinger told the panel.

But rights groups say some have been tortured anyway and that the U.S. is violating the treaty in other ways.