Russia's new nuclear drone submarine could be capable of causing 300ft-high tsunamis, able to wipe out coastal cities, experts say.

The existence of the drone, believed to be the Status-6 system - also known as 'Putin's doomsday machine' - was confirmed by the Russian President himself in his annual state-of-the-nation speech in Moscow last month.

Experts say a 50 megaton underwater nuclear bomb would be able to create tsunami waves reaching more than 320ft - the 'Status-6' is allegedly able to carry a 100 megaton warhead.

Destroyer: Russia's new nuclear carrying drone submarine - Status-6 - would be able to create devastating tsunamis if dropping warheads underwater, according to experts

The Status-6 is reported to have a range of up to 6,200 miles with top speeds of 56 knots, and an ability to carry nuclear warheads within range of the US.

In his speech on March 1, Putin said the high-speed underwater drone also has an 'intercontinental' range and is capable of carrying a nuclear warhead that could target both aircraft carriers and coastal facilities.

He said its operational depth and high speed would make it immune to enemy intercept, adding: 'It's just fantastic!'

Physicist and nuclear-weapons researcher Rex Richardson told Business Insider that an underwater warhead dropped by the drone could destroy coastal cities.

Dangerous: A video showed during President Putin's speech last month showed a nuclear warhead being launched from the drone submarine carrier

Putin's arsenal: The new nuclear weapons announced by Putin in March, including the underwater drone carrier, seen bottom centre, believed to be named Status-6

'A well-placed nuclear weapon of yield in the range 20 megatons to 50 megatons near a seacoast could certainly couple enough energy to equal the 2011 tsunami [In Japan which killed nearly 16,000 people], and perhaps much more.

'Taking advantage of the rising-sea-floor amplification effect, tsunami waves reaching 100 meters [328 feet] in height are possible.'

Mr Richardson added that such an underwater nuclear bomb dropped off the coast of the United States would be able to cause catastrophic damage to cities such as Los Angeles or San Diego through radioactive fallout rains.

Vlad's new bag of toys: Putin claims that Status-6's operational depth and high speed would make it immune to enemy intercept

The 'Status-6' was one of several new nuclear weapons which President Putin announced as having undergone tests in recent months.

In the state-of-the-nation speech, Putin said the arsenal include a nuclear-powered cruise missile, a new hypersonic missile and showed video footage the launch of a new heavy intercontinental ballistic missile on big screens.

During his speech, Putin said the creation of the new weapons has made NATO's U.S.-led missile defense 'useless,' and means an effective end to what he described as Western efforts to stymie Russia's development.

Speaking of the new arsenal, Putin said that the nuclear-powered cruise missile tested last fall has an unlimited range and high speed and maneuverability allowing it to pierce any missile defense.