Under the Geneva Conventions, the temporary failure to disclose the identities of prisoners to the Red Cross is permitted under an exemption for military necessity. But the Army generals said they were certain that the practice used by the C.I.A. in Iraq went far beyond that.

The disclosure added to questions about the C.I.A.'s practices in Iraq, including why the agency took custody of certain Iraqi prisoners, what interrogation techniques it used and what became of the ghost detainees, including whether they were ever returned to military custody. To date, two cases have been made public in which prisoners in C.I.A. custody were removed from Iraq for a period of several months and held in detention centers outside the country.

The report leaves several unanswered questions.

Another question left unanswered on Thursday was why Col. Thomas M. Pappas, the military intelligence officer who oversaw interrogations at the prison, agreed to let C.I.A. officers use the prison to hide ghost detainees. The Army report said that when Colonel Pappas raised questions about the practice, a top military intelligence officer in Baghdad at the time, Col. Steven Boltz, encouraged him to cooperate with the C.I.A. because "everyone was all one team." Still, General Kern said Colonel Pappas should have challenged the practice.

The dislosures drew strong reactions from Senators:

The new disclosures about unregistered prisoners drew angry criticism from Democrats and Republicans, and a promise from Senator John W. Warner, Republican of Virginia and the committee chairman, to hold a separate hearing.
Senator John McCain, Republican of Arizona, said, "The situation with C.I.A. and ghost soldiers is beginning to look like a bad movie."

Who's responsible?