The US Defense Department approved interrogation techniques in April 2003 for use at the Guantanamo Bay prison that permit reversing the normal sleep patterns of detainees and exposing them to heat, cold and "sensory assault," The Washington Post reported Sunday.

The classified list of about 20 techniques was approved at the highest levels of the Pentagon and the Justice Department, and represents the first publicly known documentation of an official policy permitting interrogators to use physically and psychologically stressful methods during questioning, the front-paged report said, quoting defense officials.

The use of any of these techniques requires the approval of senior Pentagon officials, and in some cases, of the defense secretary, the report said.

"These procedures are tightly controlled, limited in duration and scope, used infrequently and approved on a case-by-case basis"for use against "unlawful combatants picked up on the battlefield"who might contribute to intelligence gathering about the Sept. 11 attacks, Bryan Whitman, a Pentagon spokesman, was quoted as saying.

Similar guidelines have been approved for use on "high-valued detainees" in Iraq, defense and intelligence officials said.

It was not known whether similar guidelines were in effect at the US-run Abu Ghraib prison outside Baghdad, which has been the focus of controversy in recent days, but lawmakers have said they want to know whether the misconduct at the prison was an aberration or whether it reflected an aggressive policy taken to inhumane extremes, according to the report.

Since the Sept. 11, 2001, attacks, the US military and the Central Intelligence Agency have detained thousands of foreign nationals at the prison at Guantanamo Bay in Cuba, as well as at facilities in Iraq and elsewhere, as an effort to crack down on suspected terrorists and to quell the insurgency in Iraq.

The Pentagon guidelines for Guantanamo were designed to give interrogators the authority to prompt uncooperative detainees to provide information, thought expert on interrogation say information submitted under such conditions is often unreliable, the report said.

Source: Xinhua