Putin: Developing Russia's nuclear forces 'absolute priority'

President Vladimir Putin said Sunday that developing Russia's nuclear forces was now an "absolute priority" following the expiry of its last remaining nuclear treaty with the US.

"The development of the nuclear triad, which guarantees Russia's security and ensures effective strategic deterrence and a balance of forces in the world, remains an absolute priority," Putin said in a video message.

His speech came on Russia's "Defender of the Fatherland Day", a holiday that is an occasion for military pomp and Kremlin-sponsored patriotism.

Putin vowed to keep "strengthening the army and navy" and draw on military experience from the nearly four-year conflict in Ukraine.

All branches of the armed forces would be improved, he said, including their "combat readiness, their mobility, and their ability to operate in all conditions, even the most difficult".

Putin's remarks came just two days before the fourth anniversary of Russia's assault on Ukraine that sparked a war that has shattered towns, uprooted millions and killed large numbers on both sides.

Moscow and Washington -- the world's two main nuclear powers -- are no longer bound by any arms control pact since the New START agreement expired earlier this month.

But Russia said it would continue taking a "responsible" approach to strategic nuclear capability and respecting the limits set on its arsenal.