Russia has announced a new national security doctrine which places a greater reliance on nuclear weapons.

The document, approved by the acting President, Vladimir Putin, envisages a nuclear response if all other means of repulsing armed aggression fail.

Russia previously said it would only resort to nuclear weapons if its very existence was threatened.

A Russian military spokesman Col-Gen Valeriy Manilov denied suggestions that the doctrine was anti-Western.

But the BBC defence correspondent says the shift in strategy will cause some unease in the West --- not least because the document suggests a world where the military threats to Russia are growing.

The new doctrine also says Russia will step up its fight against terrorism and organised crime.

From the newsroom of the BBC World Service