A man has been arrested in Somerset on suspicion of offences under the Terrorism Act.
Police are searching a property in Paulton after he was held on suspicion of making or possessing an explosive substance.
Officers wearing protective clothing are carrying out the search, and the Explosive Ordnance Disposal Team has been called as a precaution.
The suspect, who is 33 and from Somerset, is in police custody.
Chf Insp Steve Kendall said “There is no wider threat to the public.”