Russia has developed a miniaturized nuclear power unit for cruise missiles and underwater drones which could potentially give them unlimited range.

"Russia has completed the trials of miniaturized nuclear power units for cruise missiles of unlimited range and for autonomous submersibles of an oceanic multi-purpose system. To date, those technologies have been designed and put into practice only by Russia," TASS reported quoting an unnamed government source.

No further details of the nuclear power unit were provided in the TASS report which suggested that the missiles with nuclear-powered engines could thwart Western missile shields.

The source said that Russia had sent signals to "its uncooperative Western partners" in the past, intended to show them "the futility of their attempts to neutralize our strategic potential by the deployment of missile shield elements."

Those signals included a leak several years ago about Russia’s project to build underwater drones of unlimited range, in a bid to spur a dialogue on global security with Western partners.

"Instead, our Western counterparts have made a serious mistake because of their illusion of superiority and technological advantage. They have chosen to ignore our signals. Now it’s they who have to catch up and bear all due consequences, first of all for the purses of their taxpayers," the source said.

On Thursday, in his speech to the Federal Assembly Russian President Vladimir Putin unveiled the most advanced systems of strategic weapons, developed in response to Washington’s unilateral withdrawal from the Anti-Ballistic Missile Treaty (ABM Treaty) and practical deployment of missile shield elements both inside the US and outside its borders.

Among the new cutting-edge weapons are the Sarmat intercontinental ballistic missile, the Kinzhal hypersonic weapons system, a nuclear-armed cruise missile, as well as a dual-capable unmanned underwater vehicle, which is meant for conventional and nuclear missions.