The White House has said fresh allegations of abuse of prisoners in Iraq and Guantanamo Bay by US military personnel will be "fully investigated".
Allegations of abuse at Abu Ghraib have rocked the US military
A White House spokesman promised those responsible would be held to account and measures taken to avoid a repeat.
Memos between FBI officials detailing abuses, some dated after the Abu Ghraib jail scandal, were released as part of a legal case against the government.
The case is being brought by the American Civil Liberties Union (ACLU).
Scott McClellan, official spokesman for US President George W Bush, said: "The president expects that if there are allegations of abuse, that those allegations need to be taken seriously.
"They need to be fully investigated. People need to be held accountable and brought to justice if they're involved in wrongdoing, and preventative measures and corrective measures put in place to prevent it happening again."
He said other allegations that Pentagon interrogators at Guantanamo pretended to be FBI agents to avoid possible blame were a matter for Defence Secretary Donald Rumsfeld.
ACLU executive director Anthony Romero said the documents raised grave questions about who was to blame for widespread detainee abuse.
Last week documents released for the case threw up fresh revelations of abuse in Iraq by US marines, 13 of whom have been convicted and some jailed.
The documents, obtained through the Freedom of Information Act, are mostly made up of communications between FBI agents concerned at seeing interrogation techniques they are prohibited from using themselves.
One of the memos released on Monday provided the account of an agent who observed "serious physical abuses" in Iraq.
It was dated 25 June - two months after the extent of abuse at Baghdad's Abu Ghraib prison was revealed - and was marked "urgent" and sent to FBI Director Robert Mueller.
It described strangulation, beatings and the placing of lit cigarettes into detainees' ears.
Another document said an executive order signed by President George W Bush had authorised techniques such as "sleep management", stress positions, use of military dogs and sensory deprivation.
The White House was quick to respond to this allegation, saying: "What the FBI agent wrote in the e-mail is wrong. There is no executive order on interrogation techniques."
A document relating to Guantanamo suggests that detainees were shackled to the floor in foetal positions for more than 24 hours at a time, left without food and water and allowed to defecate on themselves.
Other allegations contained in the e-mails include:
The Pentagon has not commented on the latest allegations of abuse, but spokesman Bryan Whitman denied that Mr Wolfowitz had approved impersonation techniques.
- That military interrogators impersonated FBI agents, apparently to avoid possible blame in subsequent inquiries
That this method was approved by Deputy Defence Secretary Paul Wolfowitz
- The rape of a juvenile male detainee at Abu Ghraib prison, currently under investigation
- That one Guantanamo detainee was wrapped in an Israeli flag and bombarded with loud music in an apparent attempt to soften his resistance to interrogation.
The department has also said in relation to previous cases that it did not tolerate abusive tactics.
Some allegations in the documents are under investigation, the Pentagon added.