The officials said these terrorists had phone calls from Pakistan, Turkey and England in order to launch insurgency activities in different parts of the city.
Majid Rozy, Herat police chief said, four of the militants were arrested from Mir-Dawood area and the rest were detained in Guzra district of Herat province.
A number of weapons and ammunitions were also discovered from the militants, He added.
The officials however did not provide details regarding the exact date of the detention.
Herat is a relatively insecure province in the West and the Taliban insurgents are active in some districts of the province.