The Pittsburgh synagogue massacre suspect exchanged messages with far-right extremists in Britain, it has been revealed.

Sources confirmed to The Times that Robert Bowers, 46, was in touch with neo-Nazis in Britain who subscribe to the conspiracy theories about Jewish control of the world.

He used Gab, the social media popular amogn extremists that was closed in the wake of the last Saturday's shooting, in which 11 people died on October 27.

While there is no suggestion that the British fascists were involved with the attack, there is increased concern among security services that far-right extremists could seek to copy imitate the attack.

Bowers – who is accused of using an assault rifle and three handguns to carry out the attack at the Tree of Life Synagogue – is known to have used Gab as a means of communication with other extremists.

The website calls itself a "free speech" alternative to Facebook  and has earned the nickname "Twitter for Nazis."

Bowers, who pleaded not guilty to 44 charges relating to the Pittsburgh attack, used Gab to share anti-Jewish images and messages relating to claims of worldwide control.

Last week, the JC revealed how pro-Tommy Robinson websites in the UK were littered with antisemitic messages.

Prevent, the deradicalisation programme, has reported a big increase in referrals of right-wing extremists over the past year.