The statement by Secretary Rice, at a congressional hearing, underlined the degree of concern in Washington over the violent protests in Afghanistan and Pakistan over the desecration charges.
Opening a round of budget testimony before a Senate Appropriations subcommittee, Ms. Rice said Americans honor the sacred books of all the world's great religions, and that disrespect for the Koran is not now, nor has it ever been or ever will be, tolerated by the United States.
The Secretary said the abuse allegations at Guantanamo are being fully investigated by military authorities, and if they are proven true, the United States will take appropriate action.
In the meantime, she appealed to those in the Muslim world to reject political incitement, in order to help avoid further violence. "During the past few days, we have heard from our Muslim friends around the world about their concerns on this matter. We understand and share the concerns. Sadly, some people have lost their lives in violent demonstrations. I am asking that all our friends around the world reject incitement to violence by those who would mis-characterize our intentions," she said.
Several people have been killed in Afghanistan in anti-American protests ignited by a report in the U.S. magazine Newsweek that interrogators at Guantanamo desecrated a Koran in an effort to un-nerve detainees.
Echoing earlier remarks by the State Department, Ms. Rice said respect for the religious freedom of all individuals is one of the founding principles of the United States, and that disrespect for the Koran is abhorrent to all.
The State Department has said the alleged incident, if it occurred, is completely at variance with standard practice at Guantanamo, where elaborate procedures have been put into effect to facilitate the practice of religion by detainees.
The detention facility, opened in 2002, currently holds about 520 detainees, many of them al-Qaida and Taleban suspects of various nationalities detained in 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 their countries of origin.