U.S. officials say the Defense Department is investigating a report that interrogators at the U.S. detention center at Guantanamo Bay, Cuba desecrated the Koran in an effort to pressure Muslim inmates. The State Department said such abuse would be reprehensible.

The reported abuse of the Koran at the detention site has triggered a Pentagon inquiry and a vigorous condemnation by the State Department, which says such activity would be reprehensible and contrary to U.S. policy.

The U.S. magazine Newsweek said in its latest edition that interrogators at Guantanamo used the tactic to try to rattle terrorist suspects, and that on at least one occasion a copy of the Muslim holy book was flushed down a toilet.

The Newsweek account spurred anti-U.S. demonstrations in Pakistan and Afghanistan and a diplomatic complaint from the Pakistani government, which demanded an investigation and punishment for the perpetrators of what it termed a shameful act.

At a news briefing, acting State Department spokesman Thomas Casey said U.S. officials agree the press report is troubling and merits investigation: "The allegations out there are certainly serious, and it would be important to have them be looked into. I know the U.S. military, you can check with (them) on this, would treat any kinds of violations of religious rights of detainees very seriously. Obviously the destruction of any kind of holy book, whether it's a Bible or Koran, or any other document like that, is something that is reprehensible and not in keeping with U.S. policies or practices," he said.

A senior official here said later a Pentagon inquiry into the desecration charge had begun, though he provided no details.

A broader investigation of alleged abuse of detainees at Guantanamo has been under way for some time.

The Guantanamo facility was opened in 2002 as the central holding point for people captured in the U.S. global war on terrorism. It still holds about 520 prisoners, many of them al-Qaida and Taleban suspects of various nationalities detained after the U.S.-led invasion of Afghanistan.

More than 200 of the original detainees have either been sent home and released, or transferred to the custody of foreign governments.