In a report for the United Nations' Committee against Torture, the London-based human rights group also alleged abuses within the U.S. domestic law enforcement system, including use of excessive force by police and degrading conditions of isolation for inmates in high security prisons.

"Evidence continues to emerge of widespread torture and other cruel, inhumane or degrading treatment of detainees held in U.S. custody," Amnesty said in its 47-page report.

It said that while Washington has sought to blame abuses that have recently come to light on "aberrant soldiers and lack of oversight", much ill-treatment stemmed from officially sanctioned interrogation procedures and techniques.

"The U.S. government is not only failing to take steps to eradicate torture, it is actually creating a climate in which torture and other ill-treatment can flourish," said Amnesty International USA Senior Deputy Director-General Curt Goering.

The U.N. committee, whose experts carry out periodic reviews of countries signatory to the U.N. Convention against Torture, is scheduled to begin consideration of the United States on Friday. The last U.S. review was in 2000.

It said in November it was seeking U.S. answers to questions including whether Washington operated secret detention centers abroad and whether President George W. Bush had the power to absolve anyone from criminal responsibility in torture cases.

The committee also wanted to know whether a December 2004 memorandum from the U.S. Attorney General's office, reserving torture for "extreme" acts of cruelty, was compatible with the global convention barring all forms of cruel, inhumane or degrading treatment.

UNTIL THE END

In its own submission to the committee, published late last year, Washington justified the holding of thousands of foreign terrorism suspects in detention centers abroad, including Guantanamo Bay in Cuba, on the grounds that it was fighting a war that was still not over.

"Like other wars, when they start, we do not know when they will end. Still, we may detain combatants until the end of the war," it said.

The U.S. human rights image has taken a battering abroad over a string of scandals involving the sexual and physical abuse of detainees held by American forces in Afghanistan, Iraq and Guantanamo Bay.

In its submission, Washington did not mention alleged secret detention centers.

Amnesty listed a series of incidents in recent years involving torture of detainees in U.S. custody, noting the heaviest sentence given to perpetrators was five months in jail.

This was the same punishment you could get for stealing a bicycle in the United States, it added.

"Although the U.S. government continues to assert its condemnation of torture and ill-treatment, these statements contradict what is happening in practice," said Goering, referring to the testimony of torture victims in the report.