A Lancashire man is among 11 men arrested by counter terrorism police following an investigation into banned extreme right-wing group National Action.
Six of the men are from the north west, including one man who has been produced from prison in Lancashire, while two are from the South Wales area, two are from the West Yorkshire area and one is from the Wiltshire area.
Their ages range from 22 to 35.
Officers from Counter Terrorism Policing North East and North West, supported by Wales Extremism and Counter Terrorism Unit and Wiltshire Police conducted the arrests, a spokesman for Greater Manchester Police said.
The force did not say which prison the man was produced from.
The arrests today result from two separate investigations and follow activity earlier this month by the West Midlands Counter Terrorism Unit.
The men from the north west are a 24-year-old from Seaforth, a 23-year-old from Newton-le-Willows, a 33-year-old from Prescot, a 31-year-old from Warrington, and a 35-year-old from Warrington.
They have all been arrested on suspicion of preparation of a terrorist act, funding terrorism and membership of a proscribed organisation.
The 22-year-old man from Lancashire was produced from prison for police interview on suspicion of preparation of a terrorist act and membership of a proscribed organisation.
A 28-year-old man from Swansea was arrested on suspicion of membership of a proscribed organisation and possession of terrorism material/documents, and a 23-year-old man from Swansea was arrested on suspicion of membership of a proscribed organisation.
A 23-year-old man from Sowerby Bridge, West Yorkshire, was arrested on suspicion of membership of a proscribed organisation along with a 26-year-old man from Leeds, while a 30-year-old man from Wiltshire was also arrested on suspicion of the same offence.
Assistant Chief Constable Russ Jackson, who is responsible for counter-terrorism policing for the north west, said: "Individuals involved in proscribed organisations who support extremist ideologies bring damaging consequences to local communities but, with the help of the public and our partners, we will do everything we can do to bring these people to justice."
Eleven properties are also being searched, police said.
The arrests follow several others in connection with National Action earlier this month.
National Action became the first extreme right-wing group to be banned under terrorism laws in December 2016.
The proscription meant that being a member of or inviting support for the organisation is a criminal offence carrying a sentence of up to 10 years' imprisonment.
In the official list of proscribed groups, it is described as a ''racist neo-Nazi group'' that was established in 2013 and has branches across the UK which ''conduct provocative street demonstrations and stunts aimed at intimidating local communities''.
The document adds that the group is ''virulently racist, anti-Semitic and homophobic'' and says its activities and propaganda materials are particularly aimed at recruiting young people.
Deputy Assistant Commissioner Neil Basu, the senior national co-ordinator for counter-terrorism policing, said: "CT (counter terrorism) policing is committed to tackling all forms of extremism that threatens public safety and security.
"Investigations relating to alleged extreme right-wing activity are pursued with the same level or resource and vigour as other ideologies, in order to bring suspected offenders before the courts.
"Today's arrests, while resulting from two separate investigations, have been coordinated by our officers across a number of forces. This maximises operational effectiveness for police and minimises disruption for the local communities."
Mr Jackson added: "We are committed to taking positive action such as this to remove those connected to organisations, such as National Action, from our communities.
"All information received will be dealt with in the strictest confidence and can be passed to us anonymously by calling the anti-terrorism hotline on 0800 789 321"
Police cars and uniformed officers remained outside a house on Greymist Avenue in Warrington on Wednesday.
Residents said police arrived at the quiet cul-de-sac between 5am and 6am and began searching the semi-detached house.
One neighbour said: "My husband tried to go to work at 6am and the road was just full of police."
She said the house was lived in by a couple and their three children - aged in their 20s or 30s.
She said: "They just keep themselves to themselves. I've seen them walking about. It's an older couple with two boys and a girl."
Another resident said the family had lived there for about 30 years.
He said: "They never speak to anybody. I don't know them.
"There's never been any kind of trouble at the house before."
One woman said she had lived on the street for about a year but rarely saw the family.
She said: "There's a lad who lives there who's probably in his late 20s to mid-30s and he lives there with his dad and mum."
She added: "The police have been coming and going to the house all day."