Everything we know about Russia's Oreshnik missile

If Putin's description is correct, the missile is at the upper edge of the definition of hypersonic, and few things can achieve this.

Speed is important because the faster a missile travels, the quicker it gets to target. The quicker it gets to target, the less time a defending military has to react.

A ballistic missile generally gets to target by following an arcing path up into the atmosphere and a similar one down towards its destination.

But as it descends, it picks up speed and gains kinetic energy, and more kinetic energy gives it more options. This allows it to manoeuvre down towards the target - by performing some kind of defending wriggle - that makes interception by surface-to-air missile systems (such as Ukraine's US-built Patriot defence missile system) particularly difficult.

This is not new for militaries that have to defend against such threats of course, but the greater the speed, the harder it becomes.

That is why Putin has likely placed emphasis on its speed in announcing this new type of missile.

Some 80% of the missiles fired by Russia have been intercepted by Ukraine, an extraordinary figure. But these faster speeds of ballistic missiles are intended to try to bring that percentage down.

Russian military expert Ilya Kramnik told the newspaper Izvestiya it is likely that the new missile, whose development has been classified until now, is at the upper end of medium-range missiles.

'It is likely that we are dealing with a new generation of Russian intermediate-range missiles [with a range of] 2,500-3,000km [1,550-1,860 miles] and potentially extending to 5,000km [3,100 miles], but not intercontinental," he says.

This could put almost the whole of Europe within range, but not the US.

"It is obviously equipped with a separating warhead with individual guidance units," Kramnik added.

He suggested that it could be a reduced version of the Yars-M missile complex, which is an ICBM.

Russia was reported to have started production of a new version of this missile complex last year which included much more mobile independent warheads.

Another expert, Dmitry Kornev, told the paper the Oreshnik could have been created on the basis of the shorter-range Iskander missiles - already commonly used on Ukraine - but with a new-generation engine.

An Iskander with an enlarged engine was used at the Kapustin Yar test site in southern Russia last spring, he said, adding that this may well have been the Oreshnik. Thursday's missile was fired into Ukraine from the same site.