Updated

Newsweek magazine Sunday apologized for a May 9 report alleging U.S. interrogators flushed the Quran down the toilet at Guantanamo Bay, a claim that had prompted attacks in Pakistan, Afghanistan and the Gaza Strip that left 15 dead and scores more injured.

"We regret that we got any part of our story wrong and extend our sympathies to victims of the violence and to the U.S. soldiers caught in its midst," Editor Mark Whitaker wrote in the magazine's latest issue.

In response to the demonstrations and subsequent deadly clashes that sparked promises by the U.S. for an investigation, about 500 Islamic scholars and tribal elders gathered in Faizabad (search), 310 miles northeast of Afghanistan's capital, Kabul (search). The scholars called for a resolution mandating anyone found to have abused the Quran (search) to be punished, said Maulawi Abdul Wali Arshad, head of the religious affairs department in Badakhshan province.

Arshad and the provincial police chief said the scholars demanded a "reaction" from U.S. authorities within three days, but they denied reports that the scholars threatened to declare a holy war if the deadline was not respected.

The controversial Newsweek report said U.S. military investigators found evidence that interrogators had placed copies of Islam's holy book in washrooms and had flushed one down the toilet in efforts to get inmates to talk.

Newsweek Washington Bureau Chief Daniel Klaidman said the magazine believes it erred in reporting the allegation and that military investigators had confirmed the accusation.

"The issue here is to get the truth out, to acknowledge as quickly as possible what happened, and that's what we're trying to do," Klaidman told the "CBS Evening News" on Sunday.

Whitaker wrote that the magazine's information came from "a knowledgeable U.S. government source," and before publishing the item, writers Michael Isikoff and John Barry sought comment from two Defense Department officials. One declined to respond, and the other challenged another part of the story but did not dispute the Quran charge, Whitaker said.

But on Friday, a top Pentagon spokesman told the magazine that a review of the military's investigation concluded: "It was never meant to look into charges of Quran desecration." The spokesman also said the Pentagon had investigated "other desecration charges by detainees and found them 'not credible."'

Whitaker added that the magazine's original source later said he could not be sure he read about the alleged Quran incident in the report they cited, and that it might have been in another document.

"Top administration officials have promised to continue looking into the charges, and so will we," Whitaker wrote.

On Aug. 1, 2002, an FBI agent who went to Gitmo made a report detailing statements from a detainee who said a U.S. official had flushed the Quran, sources told FOX News. The FBI did not confirm that this allegation was true, but it did pass on a report about the detainee's statement to the Department of Defense, U.S. officials said.

Several U.S. officials told FOX News they have no evidence of the incident, which they said could have been triggered by a released detainee making unfounded allegations.

On Thursday, Joint Chiefs of Staff Chairman Gen. Richard Myers said a guard claimed a detainee was ripping pages out of a Quran and putting them in the toilet to stop it up as a protest.

Officials at Guantanamo keep detailed logs of detainee actions, as well as what at times have been considered questionable countermeasures taken by guards that human rights groups have charged amount to abuse, officials said.

Many of the 520 inmates at Guantanamo are Muslims arrested during the U.S.-led war against the Taliban and its Al Qaeda allies in Afghanistan.

National Security Adviser Stephen Hadley said in a televised interview that the allegations were being investigated "vigorously."

"If it turns out to be true, obviously we will take action against those responsible," he said.

FOX News' Anna Persky, Bret Baier, Nick Simeone and Heather Scroope and The Associated Press contributed to this report.