Vladimir Putin has approved changes to Russia’s nuclear doctrine, setting out new conditions under which the country would consider using its arsenal. The doctrine now says an attack from a non-nuclear state, if backed by a nuclear power, will be treated as a joint assault on Russia.

He declared that a conventional attack by any nation supported by a nuclear power will be considered a joint attack on Russia.

President Vladimir Putin has updated Russia’s nuclear doctrine, two days after his American counterpart Joe Biden granted Ukraine permission to strike targets deep inside Russia with US-made weapons.