About 200 Afghans demonstrated outside the main U.S. military base in the country on Tuesday after a report that foreign troops had improperly disposed of a large number of Korans and other religious materials.

General John Allen, commander of the International Security Assistance Force (ISAF), offered his sincere apologies for the actions in an apparent bid to prevent anti-Western anger from spreading across Afghanistan.

When we learned of these actions, we immediately intervened and stopped them. The materials recovered will be properly handled by appropriate religious authorities, he said.

This was not intentional in any way.

The protests, which authorities described as largely peaceful, took place outside Bagram airfield, an hour's drive north of the capital Kabul.

It also houses a prison for Afghans detained by American forces. The centre has sewn resentment among Afghans because of reports of torture and ill-treatment of suspected Taliban prisoners.

Allen did not provide details on the incident. The Koran is the holy book of Islam.

Roshna Khalid, the provincial governor's spokeswoman, said Korans had been burnt inside the base and some of the material had been taken outside the facility, citing accounts from labourers.

Protests raged for three days across Afghanistan in April last year after a U.S. pastor burned a Koran in Florida.

Eleven people were killed when demonstrators stormed a U.N. compound in the northern city of Mazar-i-Sharif, including seven foreign U.N. workers. Another riot in the southern city of Kandahar left nine dead and more than 80 wounded.

(Reporting by Samar Zwak; Writing by Michael Georgy; Editing by Nick Macfie)