On Thursday, gunmen in Afghanistan shot dead two Finnish women working for a Christian aid charity in the western city of Herat.
A local governor said the women had been travelling by taxi when gunmen on a motorcycle fired on their vehicle.
The attacks come at a tense time for Afghanistan.
The majority of foreign troops are preparing to leave by the end of the year, and votes are being rechecked in a fiercely disputed presidential election to choose a successor to Hamid Karzai.