Alleged members of a banned neo-Nazi group arrested on suspicion of preparing acts of terror are serving members of the Army, the Ministry of Defence has said.

The men are a 22-year-old from Birmingham, a 32-year-old from Powys, a 24-year-old from Ipswich and a 24-year-old from Northampton.

West Midlands Police is holding them on suspicion of being members of British far-right group, National Action.

All four are being held at a police station in the West Midlands. Police said the arrests had been pre-planned and intelligence-led, and there had been no threat to the public’s safety.

The men are being held on suspicion of being concerned in the commission, preparation and instigation of acts of terrorism under Section 41 of the Terrorism Act 2000; namely on suspicion of being members of a proscribed organisation.

 National Action, a British far-right movement, was banned last year by Home Secretary Amber Rudd. Being a member of – or inviting support for – a proscribed organisation is a criminal offence carrying a sentence of up to 10 years in prison.

National Action describes itself as a “National Socialist youth organisation” and says its movement is aimed at the “broken right-wing”. Ms Rudd called it “a racist, anti-Semitic and homophobic organisation”.

The official register of proscribed groups says it was established in 2013 and has branches across the UK which “conduct provocative street demonstrations and stunts aimed at intimidating local communities”.

It is particularly aimed at recruiting young people, according to the list.