British police secure the perimeter outside RAF Mildenhall, England, after an incident and a suspect was arrested after a disturbance at the base, Monday Dec. 18, 2017. The Midenhall airbase, about 80 miles (130 kilometers) north of London, is used by the U.S. Air Force, and was briefly locked down and a man was taken into custody after a disturbance Monday, police said. (Graham Clark/PA via AP)

London - British police have arrested five men and one woman on suspicion of belonging to a banned far-right extremist group.

West Midlands Police said the six suspects aged between 21 and 37 were arrested Wednesday under the Terrorism Act.

They are accused of belonging to National Action, which was banned in 2016. At the time it was the first far-right extremist group outlawed in Britain.

Police are searching several properties in relation to the arrests.

The six suspects have not been charged or identified. They are being questioned by counter-terrorism police.

Police say the arrests were pre-planned and there is no threat to public safety.