Five houses in Stoke-on-Trent have been raided by police as part of an inquiry into a gang suspected of promoting extremist views and radicalising vulnerable people.
The properties include three in Cobridge, one in the High Lane area of Burslem and one in Tunstall, Staffordshire Police said.
A spokesman said the raids were part of an "ongoing investigation into the activities of a small group of people suspected of being involved in promoting violent extremist views and radicalising vulnerable community members".
He added: "They are being conducted under the Terrorism Act and have been prompted by concerns about the activities of a small number of people in the local community."
The raid at the Tunstall property was completed on Tuesday, the force said, but no-one has been arrested.
Detectives stressed that they had acted upon the community's concerns and said the operation was the "latest stage of the force's investigation to resolve them and help establish the facts".
The operation posed no direct risk to public safety, a police statement said.
Chief Superintendent Jane Sawyers, divisional commander for Stoke-on-Trent, said: "I am extremely proud of the strong community relations we have in the city and would ask for the public's continued support and vigilance.
"We can only tackle the real and serious threat posed to us all by violent extremism if we all work together."
She added: "We are working closely with our communities to support everyone by keeping them informed about today's operation."