Allegations that foreign troops in Afghanistan burnt copies of the Koran has led to extra security measures at the US embassy in Kabul.
Protests that began in Bagram, on Tuesday after the claims were made, have now spread to the capital.
The US embassy there has cancelled all travel and is warning its staff to be particularly careful.
Seventy year old protester Khan Gul was enraged:
“Death to the American puppets, death to their agents who brought them to this country. They are insulting this holy country and its people. They are double-crossing us. Death to America!” he shouted outside the US military’s Camp Phoenix in Kabul.
Apologies came from both the commander of the NATO forces in Afghanistan and the White House on Tuesday.
“This was a deeply unfortunate incident that does not reflect the great respect that military has for the religious practices of the Afghan people. Our military leaders have apologised, as I mentioned, for this unintentional action and ISAF is leading an investigation to understand what happened,” said White House spokesman Jay Carney.
The unrest began at the US military base in Bagram on Tuesday, and helicopters fired flares to try and disburse the crowd.
Labourers claim to have found the remnants of burnt copies of the Koran when they were collecting rubbish from the airbase.