By Andrew North
BBC News, Kabul
Protesters burnt an effigy of US President Obama
There have been protests in the Afghan capital, Kabul, over allegations that foreign troops in the country burnt a copy of the Koran.
Hundreds of Kabul University students led the latest protest, burning an effigy of US President Barack Obama.
The US-led Nato force has denied the claims, saying it has investigated the incident in Wardak province and found the allegations to be groundless.
The local authorities there have so far supported Nato.
They say they did find evidence that a Koran had been burnt, but blamed drug addicts and said the Taliban may be spreading rumours that foreign troops were responsible to provoke anti-American unrest.
On Sunday, a crowd estimated in the high hundreds marched through Kabul - chanting "Death to America" - to protest at the alleged desecration of the Islamic holy book earlier this month.
There were some clashes with security forces, and Afghan police fired in the air to scatter the crowd.
But protesters said they would not give up.
"We are demonstrating because American soldiers burned our holy Koran in Wardak province," said one man. "We will keep going to embarrass the Americans for their actions."
In this very religious country, any allegation like this has an incendiary effect.
Four years ago, almost 20 people were killed after riots erupted in several Afghan cities following a US news magazine report that the Koran had been desecrated by American interrogators at the Guantanamo Bay prison camp.
The magazine later withdrew its report, but by then the damage had been done.
At the time, many believed growing disenchantment among Afghans with the foreign community and its performance had helped fuel the violence.
Four years on, that record is under even greater scrutiny.