White supremacist terrorism around the globe is being manipulated by Russia for political ends, senior US national security officials have warned.

The perpetrators of white supremacist violence should now be treated as international, rather than domestic, terrorists, Joshua Geltzer, former US senior director of counter terrorism, said.

Such groups are "emulating" jihadists like Islamic State of Iraq and the Levant by forging a "transnational" community of followers, using social media and encrypted communications platforms.

Designating white supremacist groups as foreign terrorist organisations would make it easier to prosecute those who provide material support to them, and to freeze financial accounts in the US.

In testimony to a Congressional committee Mr Geltzer said: "This is not terrorism 'domestic' to any one nation alone. It is a global surge in violence inspired by white supremacy.

"There is one additional driver of today’s threat that must be emphasised - the active role of foreign government actors in propagating violent white supremacist ideology."