A 16-year-old boy is among five people arrested on Saturday morning as part of a police investigation into right-wing terrorism.
He was arrested at an address in Swindon on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism.
Also held by police were a 28-year-old woman and two men, aged 29 and 30, from Keighley, and a 28-year-old man from Anglesey.
All five have been taken to a police station in West Yorkshire to be questioned.
Counter Terrorism Policing North East said a number of properties were being searched in connection with the arrests, which are part of an ongoing investigation into right-wing terrorism.
The unit says: “We recognise that local people may have concerns as a result of this activity.
“We would like to reassure them that these arrests are pre-planned and intelligence-led and there is not believed to be any immediate risk to the local community.
“We are grateful for the understanding, patience and support of local residents while these inquiries continue.”