Thousands marched angrily through Kabul today after security forces opened fire on protesters and killed at least 13 Afghans in clashes sparked by a fatal traffic crash involving a US military truck.
The truck, part of a US convoy, had careered out of control and crashed into a dozen vehicles, killing at least one person and injuring six.
A furious crowd then hurled stones and smashed windows of the convoy vehicles, according to a US military statement.
One of the besieged US vehicles appeared to fire in the air, according to the statement. Afghan police also opened fire when they came to the assistance of the US troops, and it was unclear who was responsible for shooting into the angry crowd.
Some witnesses blamed the US troops, others blamed the police and some blamed both.
"There are indications that at least one coalition military vehicle fired warning shots over the crowd," a US military statement said.
At least seven civilians were killed during the protest, said a spokesman for President Hamid Karzai. A public health ministry official said at least 40 wounded people had been admitted to hospitals.
Mr Karzai appealed for calm, but by early afternoon up to 2,000 protesters had gathered in central Kabul, some marching on parliament and some on the presidential palace.
Several hundred more congregated at an intersection leading to the heavily fortified US embassy chanting slogans of "Death to America" and burning US flags.
A few dozen forced their way past a police cordon guarding the road to the heavily fortified US embassy and threw stones at vehicles carrying foreigners into the compound, prompting the occupants to fire in the air before turning back.
The protesters outside the embassy were later dispersed by police and Afghan army troops who fired in the air.