Donald Trump was immediately shut down by experts after he suggested the US had "more advanced” nuclear missile technology than Russia.

On Thursday, five Russian nuclear engineers were killed in a rocket engine explosion, which is thought to be linked to tests for a nuclear-powered cruise missile announced by Vladimir Putin in March 2018.

In his typically tactless style, Trump shared his thoughts on the explosion yesterday by claiming the US was “learning much” from the blast and had even more advanced technology.

Trump’s tweet caught the attention of national security experts because it meant one of two things:

Trump had just revealed a secret US nuclear-powered cruise missile programme

He was bluffing about a missile programme that the US does not have

It doesn't exactly take, ahem, a rocket scientist to know that both of those explanations are quite bad.

For example, Michael McFaul, who worked both for the US National Security Council and as Barack Obama’s Ambassador to Russia, had no idea what Trump was talking about.

Other experts on nuclear weapons couldn’t find public evidence for Trump’s claim either.

In fact, there was once a programme to develop a nuclear-powered cruise missile during the Cold War, called Project Pluto, but the US abandoned it because it was believed to be too dangerous – potentially creating missiles for which there was no known defence.

So if the US does have “more advanced” technology than Russia on this, the president should definitely not be tweeting about it.