KABUL, Afghanistan (AP) — Gunmen riding on a motorcycle opened fire and killed two Finnish women aid workers in the western Afghan city of Herat on Thursday, officials said, the latest in a series of attacks on foreign civilians that has rattled aid workers, contractors and journalists.

The two women were riding in a taxi when they were shot dead, said Sami Wafa, the chief of staff of the Herat governor. Herat police spokesman Raouf Ahmadi said the taxi driver had been detained as part of the investigation.