At least 13 Afghan police and civilians have died in two incidents involving international forces, officials say.
Four Afghan police and five civilians died in an apparently mistaken air strike by international coalition forces in Farah province.
Separately, the Nato-led Isaf said it had “accidentally” killed at least four civilians in Paktika province.
The incidents are the latest in a series of controversial clashes involving foreign troops.
They come as US Democratic presidential candidate Barack Obama is in Afghanistan as part of an overseas tour.
Mr Obama, who wants to increase US troop levels in Afghanistan, was due to meet Afghan President Hamid Karzai on Sunday.
Mr Karzai has said no civilian casualty is acceptable.