Five people have been arrested on suspicion of being members of banned far-right group National Action.
Three men, a woman and a 17-year-old boy are being questioned on suspicion of being members of the organisation, which was proscribed a terrorist group in December 2016.
They were detained on Wednesday morning following a series of raids carried out by West Midlands Counter Terrorism Unit across the country. All five are being held at a police station in the West Midlands, the force said.
Those arrested include a 22-year-old man from Birmingham, a 23-year-old man from Halifax, a 22-year-old woman also from Halifax, a 28-year-old man from Birmingham and a 17-year-old boy from Nottingham.