The United States says it’s taking “seriously” Vladimir Putin’s veiled threats to use nuclear weapons to defend areas in Ukraine.

The White House says Putin spoke irresponsibly and Washington will not change its “strategic deterrent posture”.

On Wednesday Putin warned that Russia would use all the means at its disposal to protect its territory.

It came as four Ukrainian regions, part-occupied by Russian forces are about to stage snap votes on joining Russia.

Ukraine and its allies call the votes a sham exercise, designed to give spurious legitimacy to an illegal annexation.

Top U.S White House spokesman, John Kirby, says it’s a dangerous precedent for Putin to be using that kind of rhetoric in the context of a war he’s clearly losing.

He dismissed plans for Russia to annex further parts of Ukraine as “nothing more than a ploy by Vladimir Putin to try to gain… through politics and electoral issues, that which he cannot gain militarily”.

Russia’s conduct in Ukraine was strongly condemned at a special meeting of the UN Security Council in New York today.