WASHINGTON - US military investigators have concluded that five soldiers were involved in the burning of Qurans in Afghanistan last week that was described as "accidental," US media quoted officials who have been briefed on the inquiry as saying on Friday.

The Washington Post reported on its website that the burning of the religious material began after soldiers removed the Qurans from a prison located at Bagram air base after they were found to contain extremist messages.

The books were then placed in an office for safekeeping, according to the inquiry ordered by General John Allen, commander of the International Security Assistance Force. But they were mistaken for garbage and taken to a landfill on the base.

Afghan employees identified the books as Qurans just as their pages caught fire, a major desecration, according to religious teachings. The discovery led to a week of unprecedented tension between US and Afghan military officials, as well as a week of protests that left over 30 Afghans dead. The burnings also were cited as motivation for at least some of six fatal attacks on US soldiers that have occurred in Afghanistan in the past week.

The paper quoted an anonymous official as saying what the soldiers did was "careless, but there was no ill will." US military officials said that the five soldiers will be reprimanded, it's unlikely that their names will be released or that their punishment will approach the seriousness of what some Afghans are demanding.

Top United Nations envoy to Afghanistan Jan Kubis also called on the international military forces in the country to take disciplinary action against those who burned Koran in a US military base in Afghanistan.