At least 13 people are believed to have been killed after a suicide bomber targeted a minibus near Kabul airport in Afghanistan.
Unconfirmed local-media reports have suggested the bomber was a 22-year-old woman who drove a car packed with explosives into a minibus carrying foreign aviation workers to the city's airport.
The blast was so powerful it reportedly hurled the bus at least 50 metres.
Kabul police chief General Mohammad Ayub Salangi, said nine of the men died in the blast and a further ten Afghan bystanders were wounded.
The other people killed are also believed to be Afghans.
A school teacher who witnessed the blast described how he was waiting for a bus at 6:45am when he saw a small white car drive straight into the minibus.
"The explosion was so powerful and loud that I could not hear anything for 10 minutes," said Abdullah Shah. "It was early and there wasn't much traffic or there would have been many more casualties," he added.
Insurgent group Hezb e Islami said it carried out the attack claiming it was in retaliation for a film mocking the Prophet Mohammed.
The group is led by former warlord Gulbuddin Hekmatyar, who recently sought to take part in peace-and-reconciliation efforts led by Afghan President Hamid Karzai.
Haroon Zarghoon, a spokesman for the group, claimed responsibility for the bombing in an email to the Associated Press news agency, stating it was carried out by a 22-year-old woman named Fatima.
If confirmed, it would be the first suicide-car-bombing carried out by a woman in Afghanistan.
The bombing highlights the growing anger in Afghanistan over the film - Innocence of Muslims - which has enraged much of the Muslim world.
The US-produced film calls Islam a "cancer" and portrays the Prophet as a fraud, a womaniser and homosexual.
Thousands of protesters clashed with police in the Afghan capital on Monday, burning cars and hurling rocks at security forces.
On Monday, Pakistan's Prime Minister Raja Pervez Ashraf ordered that access to YouTube, where the video has been uploaded, be suspended so that the "blasphemous" video could not be viewed.
On September 11, around 3,000 mainly Salafist demonstrators protested at the US embassy in Cairo and at the US consulate in Libya's eastern city of Benghazi, US Ambassador Chris Stevens and three more embassy officials were killed, including two ex-marines.
US President Barack Obama condemend the attack as "outrageous" but he insisted he would not break America's bond with Libya.
On Thursday, In Yemen, the US embassy was attacked and there were clashes between police and demonstrators which killed four people.
On the same day there were further protests outside the US embassy in Cairo which left 200 injured. Protests also took place in Iraq, Iran and the Gaza Strip.
On Friday, security forces in Sudan used tear gas against 10,000 demonstrators who had gathered outside the US embassy. Two protesters were killed and demonstrators also set fire to the German embassy.
In Tripoli, one person was killed after Islamists confronted security forces, while in Tunis four people were killed in fighting outside the US embassy and at a nearby American school.
According to some American officials, extremists are using hostility to the film as a pretext to launch assaults on US interests on the anniversary of the September 11, 2001 attacks.