Thousands of enraged Afghans rallied outside Bagram Air Base on Tuesday, incensed by reports that American military personnel had burned Qurans and other religious texts.

Protesters told the Washington Post that they had become aware of the incident when Afghans who work at Bagram emerged with singed fragments of holy books. Ahmad Zaki Zahed said U.S. officials subsequently led him to a burn pit containing fragments of 60 to 70 books, including Qurans, that had belonged to detainees held at the base.

Some were all burned. Some were half-burned, Zahed told the Associated Press.

Desecrating the Koran is deeply offensive to religous Muslims, and allegations of Koran-burning have proved explosive in the past. As Afghans hurled rocks at Bagram and chanted death to America, officials tried to contain the fallout.

We are thoroughly investigating the incident and we are taking steps to ensure this does not ever happen again. I assure you ... I promise you ... this was NOT intentional in any way, Gen. John R. Allen, the top Western military commander in Afghanistan, said in a statement. I offer my sincere apologies for any offense this may have caused, to the President of Afghanistan, the Government of the Islamic Republic of Afghanistan, and most importantly, to the noble people of Afghanistan.

The apparent Koran burning comes at a sensitive time, as the United States tries to negotiate the terms of the pending departure of American troops from Afghanistan. President Hamid Karzai has said that the United States and Afghanistan have made tenative contact with the Taliban in the hope of initiating peace talks, but the alleged destruction of sacred texts has intensified the anti-American sentiment central to the Taliban.

They should leave Afghanistan rather than disrespecting our religion, our faith, protester Mohammed Hakim told the Associated Press. They have to leave and if next time they disrespect our religion, we will defend our holy Quran, religion and faith until the last drop of blood has left in our body.