Local officials said the dead were employees of the Afghan Ministry of Rural Rehabilitation and Development, Khaama Press reported.
Israeel Khan, head of the criminal investigation department, confirmed the reports and said the employees had been working on a reconstruction project funded by the National Solidarity Program in Gulran district when they were abducted by the Taliban, the report said.
The report did not say when the employees were abducted.
Khan said those killed included two ministry staff members and four engineers.
Herat had been described as a relatively peaceful provinces before Taliban militants began stepping up their insurgency activities in the province's various districts.