All the Allies PR exercises of recent years were in tatters as TV stations and newspapers across the world showed graphic images of naked Iraqi prisoners being humiliated by smiling US military police.

In the Middle East, Arab TV stations led news bulletins with the photos of hooded prisoners piled on top of each other in a human pyramid and simulating sex acts, with their genitals blurred.

Many in the Middle East saw the mistreatment as the latest example of American disregard for Arabs.

"They were ugly images. Is this the way the Americans treat prisoners?" asked Ahmad Taher, 24, a student at Baghdad's Mustansiriyah University. "Americans claim that they respect freedom and democracy - but only in their country."

"The Scandal" ran a front-page headline in Egypt's government-leaning newspaper Akhbar el-Yom. "The Shame", read one in the opposition newspaper Al-Wafd.

"Shame on America. How can they convince us now that it is the bastion of democracy, freedoms and human rights?" asked Mustafa Saad, reading the morning newspapers at a downtown Cairo cafe. "Why do we blame our dictators then?"

Wahid Abdel Meguid, of the Ahram Centre for Political and Strategic Studies, said many Arabs are "psychologically prepared to condemn the United States as an enemy while forget the enemy within."

"This is a crystal-clear double standard," he said. ''Evil is evil whether it comes from foreigners or from us. Pain is pain regardless of who causes it."

Arab League secretary general, Amr Moussa, has in the past been widely criticised by Iraqis for remaining silent over the atrocities of Saddam's regime and failing to push investigations about Saddam-era mass graves. But his office expressed disgust and shock at the "despicable scenes" shown in the new photographs.

Arabs said US claims of moral superiority mean America must be held to a higher standard.

"How can the government ask others to comply with international and civilised standards while its soldiers are violating them?" said Mamdouh al-Sheikh, an independent political analyst in Cairo.

"If this mistake is not corrected and the perpetrators brought to justice, the image of the United States as a champion of freedom will be ruined."

Hurst Hannum, an international law professor at the Fletcher School at Tufts University outside Boston, said the problem is that Bush "put this war on such a high moral plane that any moral deviance will be taken more seriously by critics, and will be interpreted as either being arrogance or hypocrisy."

Anwar al-Buni, of the Human Rights Association in Syria, said the images "negate all that which the United States claims about defending human rights and democracy all over the world."

The Ministry of Defence confirmed that, prior to the latest allegations, British troops had already been investigated over a total of 10 claims of torture.