A man and a woman, thought to be a Canadian and a United States citizen, have been reported missing by a provincial reconstruction team in volatile Wardak, west of Kabul.
It's feared the pair have been kidnapped.
The police say the two had planned to travel from Kabul to Wardak but contact with them was lost.
A US Embassy spokesperson in Kabul said there was no information on a missing American, but diplomatic officials are often reluctant to talk about kidnappings in the hope it could smooth the way for negotiations on a release.
Canada's Department of Foreign Affairs said it was looking into the reports.