A suspect armed with an axe and knives has been arrested near a Territorial Army (TA) base in Kidderminster.
A 23-year-old man was arrested by armed officers close to the TA centre, although West Mercia Police said there is "no suggestion of any threat" to that premises at this stage of the investigation.
The motives of the suspect are not known, but the case is being investigated by West Midlands Counter Terrorism Unit, supported by West Mercia Police.
The incident is not thought to be related to the recent terror attack at London's Finsbury Park Mosque.
Assistant Chief Constable for West Mercia Police, Martin Evans, said: "On identifying the man our officers took prompt action to contain the threat and take him into custody.
"I understand that this will be extremely concerning for the residents of Kidderminster but I would like to reassure you that at this time we believe the suspect was acting alone and we are not looking for anyone else in connection with the incident.
"At this stage we do not believe this incident is linked to the tragic events in Finsbury Park in London last night.
"I would urge people not to speculate on what has happened. As I am sure you will appreciate, this is an extremely sensitive investigation but I can assure you that we will make information available as and when it is appropriate."