A bomb has exploded on a peacekeeping vehicle in Kabul, killing at least three and wounding 11 others.
An Afghan police official said the International Security Assistance Force bus was travelling from the airport towards eastern Kabul when the bomb was detonated.
Kabul Police Chief Basir Salangi said: "Some foreign people have died and some have been injured."
Major Sarah Wood, an ISAF spokeswoman, confirmed there were casualties aboard the vehicle, "some of which we believed are ISAF", but would not say who or how many.
"Our priority is to get them medical assistance as soon as possible," she said.
The explosion appears to be the deadliest assault on peacekeepers since they arrived in Afghanistan to bring security to the capital following the fall of the hardline Taliban regime.
Suspected Taliban fighters have been stepping up attacks since the start of spring, particularly in the south and east of Afghanistan.
Before Saturday's attack, 15 peacekeepers had died on duty in Afghanistan, all of them in accidents.
There are currently around 5,000 peacekeepers in the country. Germany and the Netherlands are in joint command, but are due to hand over control to Nato in August.
PA