The US commander of Nato troops in Afghanistan has apologised after copies of the Koran were sent to be burned in a rubbish tip.
The Korans were left in the rubbish and transported in a lorry by coalition soldiers to a pit on the Bagram air base, 60km north of Kabul, where waste is burned.
According to the BBC, five Afghans working at the tip noticed the religious books in the pile, and retrieved them. Photos of the books released by news wires showed them with partially burned pages.
Large-scale protests of up to 2,000 people erupted outside the base in response to the news.
People threw fire bombs and stones at the base, while the Reuters news service said flares were fired from helicopters to disperse the crowd.
The base where the books were burned is already controversial in Afghanistan because it has been accused of mistreating and torturing suspected Taliban fighters.
In his statement, General John R. Allen said: "when we learned of these actions, we immediately intervened and stopped them".
The general ordered an investigation and promised that the actions were not intentional.
"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.
"I would like to thank the local Afghan people who helped us identify the error, and who worked with us to immediately take corrective action."
Allen's statement was played repeatedly on local TV, in an attempt to diffuse the violence.
Ten UN workers were killed in 2011 after the news that an American preacher had burned a copy of the Koran in Florida.
The full statement read:
To the noble people of Afghanistan -
I have ordered an investigation into a report I received during the night that ISAF personnel at Bagram Airbase improperly disposed of a large number of Islamic religious materials which included Korans.
When we learned of these actions, we immediately intervened and stopped them. The materials recovered will be properly handled by appropriate religious authorities.
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.
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.
I would like to thank the local Afghan people who helped us identify the error, and who worked with us to immediately take corrective action.