Defense Secretary Donald H. Rumsfeld said yesterday that he approved the secret detention of a suspected terrorist in Iraq after receiving a request to do so from CIA Director George J. Tenet, effectively hiding the prisoner from the International Committee of the Red Cross for seven months.

Rumsfeld, in an afternoon news briefing at the Pentagon, also acknowledged that there have been other cases in which detainees have been held secretly. "There are instances where that occurs," Rumsfeld said. "And a request was made to do that and we did."

Earlier this year, an Army investigation into the abuses of detainees at Abu Ghraib prison in Iraq sternly criticized the practice of keeping "ghost detainees" -- CIA prisoners who were kept off official rolls and moved to keep them from the Red Cross. The investigative report called it "deceptive, contrary to Army doctrine and in violation of international law."

Yesterday Rumsfeld said the CIA was authorized to secretly detain suspected terrorists. And he said this prisoner, an Iraqi suspected of membership in the terrorist group al-Ansar, should not be put in the same category as the prisoners who were secretly held at Abu Ghraib.

"This individual, this Ansar al-Islam individual, I think, should be looked at separately from that," Rumsfeld said, although he said he did not know specifically how the individual's legal status would be different from that of Abu Ghraib prisoners.

Yesterday's briefing was the first time Rumsfeld has publicly addressed questions about abuses in Iraq since the public release of several internal administration documents and memos concerning U.S. policy on foreign detainees.

The documents show that a range of severe interrogation tactics was approved by high-ranking military officers for use at Abu Ghraib. Military intelligence interrogators got authority to use unmuzzled dogs to help with prisoners, for example.

Other internal documents show the administration weighed the legal issues surrounding the use of torture against detainees -- although President Bush and administration officials have repeatedly said that all prisoners in Iraq were covered by international law and that U.S. authorities were ordered to treat detainees in the war on terror humanely.

Rumsfeld said yesterday he fears news reports concerning such documents has created a dangerous and mistaken impression that U.S. policy endorses torture.

He said again that the Abu Ghraib abuses caught in alarming photographs appear to be isolated incidents at the hands of a few rogue military police soldiers. Rumsfeld said that he is monitoring several investigations that are delving into alleged abuses.

"At the moment, I have high confidence that I have not seen anything that suggests that a senior civilian or military official of the United States of America has acted in a manner that's inconsistent with the president's request that everyone be treated humanely," he said. He added that he knows of nothing that "could be characterized as ordering or authorizing or permitting torture or acts that are inconsistent with our international treaty obligations or our laws or our values as a country."

Rumsfeld yesterday defended his decision to honor the CIA's request to hold the suspected al-Ansar member without giving him an internee number or listing him on records. At the same time, he acknowledged that military personnel should have recorded the detainee's name and identification number sooner -- it has taken seven months -- so Red Cross officials could meet with the prisoner, who has not been identified.

He said that, contrary to reports that the detainee had essentially become lost in the system after his arrest, the prisoner's whereabouts were known for the entire time of his detention, and that he was treated humanely and was never at Abu Ghraib.

Rumsfeld said he also believes Tenet had the power to order such detentions. "We know from our knowledge that he has the authority to do this," Rumsfeld said, adding that the military has received other prisoners from the CIA "where they have, for some reason, captured somebody or arrested somebody or been given somebody and at some moment brought them to us and said, 'Would you please take custody of this person?' "

Tom Malinowski, a spokesman for Human Rights Watch, said the Geneva Conventions call for prompt registration of each detainee and allow governments to prevent Red Cross access only in extreme circumstances, such as when a prison is being shelled or when giving access to the prisoner would specifically put either party in immediate danger.

"I can't see what legitimate national security purpose is served by hiding people from the Red Cross," Malinowski said. "The only thing it achieves is to further tarnish America's reputation and to invite similar treatment of captured Americans. Whatever benefit the U.S. gains, if any, from using those methods, they are vastly outweighed by the damage done to American interests by treating detainees in this way."

Human rights organizations have contended for nearly three years that the Bush administration should open detention camps to greater scrutiny by the International Committee of the Red Cross. Prisoners typically have no family contact or access to legal advice or judicial review. In countless cases, their families do not know their whereabouts.

"The United States has a network of secret facilities and secret detainees that goes way beyond Afghanistan, Iraq and Guantanamo," Elisa Massimino, Washington director of Human Rights First, said yesterday, after the group released a report titled "Ending Secret Detentions."

Sen. John F. Kerry (Mass.), the Democratic presidential nominee, said yesterday that the world is getting a "muddled message" from the Bush administration regarding the alleged abuses. He said that if he were president, he would appoint a high-level official outside the Pentagon to investigate what happened.

"Every few days, folks, we learn more" than the administration is "willing to tell us," Kerry said. "Every few days we learn that this runs higher and goes deeper than they have been willing to admit. We have gone from the president's first statement that only a few people were involved to now knowing that it went up. . . . Now the secretary of defense personally approved not applying the Geneva Conventions to a prisoner in Iraq."

Staff writers Lois Romano in Detroit and Peter Slevin in Washington contributed to this report.

Defense Secretary Donald H. Rumsfeld, with Gen. Peter Pace, vice chairman of the Joint Chiefs of Staff, talks to reporters at a news conference.