Counter terrorism officers have been granted more time to question five people, including three from Keighley, on suspicion of far-right terrorism offences.
The two men, aged 29 and 30 and a woman, aged 28, were arrested along with a 16-year-old boy from Wiltshire and a 28-year-old man from Anglesey. They are all being questioned at a police station in West Yorkshire.
What has been described as 'suspicious material' has been found at a house in the town and the search of that property continues.
West Yorkshire police said:"Following the discovery of potentially suspicious material at one of the addresses in Keighley the Explosive Ordnance Disposal Unit (EOD) has been called to provide specialist advice and to arrange the safe removal of the items if required."
A number of properties are being searched in connection with the arrests.Some homes have been evacuated as a 'precuationary measure.'
The raid was part of an intelligence led investigation into suspected right wing terrorism.