Russia will no longer tell the US before carrying out missile tests, a senior Kremlin diplomat said, signalling an end to a decades-long practice that has eased the threat of nuclear escalation.

Sergei Ryabkov, Russian deputy foreign minister, said in remarks carried by Russian news agencies that Moscow had halted all information exchanges with Washington after recently withdrawing from the last remaining nuclear arms pact with the US.

The two nations have exchanged advance warnings about test launches for decades, along with information about the current state of their nuclear forces.

Such notices have been an essential element of the strategic stability that has defined relations since the winding down of the Cold War in the late 1980s, allowing Russia and the US to correctly interpret each other’s moves and make sure that neither country mistakes a test launch for a missile attack.

The termination of missile test warnings appears to mark yet another attempt by Moscow to discourage the West from ramping up its support for Ukraine by pointing out Russia‘s massive nuclear arsenals.

Mr Ryabkov’s comments came as Russia deployed Yars mobile missile launchers in three regions of Siberia in a show of the country’s massive nuclear capability amid the fighting in Ukraine.

Last month, Mr Putin suspended the Obama-era New Start treaty, saying Russia could not accept US inspections of its nuclear sites under the agreement at a time when Washington and its Nato allies had openly declared Russia’s defeat in Ukraine as their goal.

Moscow emphasised that it was not withdrawing from the pact altogether and would continue to respect the caps on nuclear weapons.

The Russian foreign ministry initially said Moscow would keep notifying the US about planned test launches of its ballistic missiles, but Mr Ryabkov’s statement reflected a change of course.

Russian officials have issued a barrage of hawkish statements since their troops entered Ukraine, warning that the continuing Western support for Kyiv raised the threat of a nuclear conflict.

Mr Ryabkov said Russia was responding to what he described as the “fundamental irresponsibility of western elites before their people and international security”.

“Now they will have to deal with changing realities,” he said, adding: “We hope that Nato officials will adequately assess the seriousness of the situation.”

Associated Press contributed to this report