In an unscheduled television appearance on Thursday, Russian President Vladimir Putin said the strike on the city of Dnipro had tested in combat conditions "one of the newest Russian mid-range missile systems".

He said missile engineers had christened the missile Oreshnik, or hazel tree in Russian.

Putin said it had been deployed "in a non-nuclear hypersonic configuration" and said that the "test" had been successful and had hit its target.

- Speed -

Air defences cannot intercept the Oreshnik, which attacks at a speed of Mach 10, or 2.5-3 kilometres per second, Putin said.

Hypersonic missiles travel at speeds of at least Mach 5 -- five times the speed of sound -- and can manoeuvre mid-flight, making them harder to track and intercept.

"Modern air defence systems... cannot intercept such missiles. That's impossible," Putin said.

"As of today there are no means of counteracting such a weapon," the president boasted.

- Warheads -

The Oreshnik missile could have three to six warheads, military expert Viktor Baranets wrote in the Komsomolskaya Pravda tabloid.

Igor Korotchenko, editor of the Moscow-based National Defence journal, told TASS state news agency that based on video footage of the strike, Oreshnik has multiple independently guided warheads.

In this case they were conventional, but it could also carry nuclear warheads, military experts said.

The "practically simultaneous arrival of the warheads at the target" shows the system is "very effective", Korotchenko said, calling it a "masterpiece of modern Russian solid-fuel military missile construction".

- Range -

The missile was reported by Ukrainian media to have been fired from the Kapustin Yar range in the Astrakhan region, around 900 kilometres (550 miles) from Dnipro.

Putin described the missile in Russian as "medium-range" but Russian military experts said the English term would be "intermediate-range".

An intermediate-range ballistic missile (IRBM) has a range of 1,000-5,500 kilometres, a level below that of an intercontinental ballistic missile (ICBM).

Military expert Ilya Kramnik told Izvestia newspaper that Oreshnik's range could be at the top end of intermediate, around 3,000 - 5,000 kilometres.

"In any case we witnessed the first combat use in history by Russia of an intermediate-range missile," Dmitry Kornev, editor of Military Russia website, told Izvestia.

- Origins -

The US Department of Defense described Oreshnik as an "experimental" missile based on Russia's RS-26 Rubezh ICBM.

Little is known about Rubezh, a modification of Topol ICBM.

TASS state news agency reported, citing a source, in 2018 that development of Rubezh was frozen under the state weapons programme up to 2027, to prioritise another system, Avangard.

Russian weapons expert Yan Matveyev wrote on Telegram that Oreshnik probably had two stages and would be "quite expensive", heavy and not mass-produced.

- Threat -

Its range means "Oreshnik can threaten practically all of Europe" but not the United States, weapons expert Pavel Podvig, director of the Russian Nuclear Forces Project, told Russian Telegram channel Ostorozhno Novosti.

The US and the Soviet Union in 1987 signed a treaty agreeing to give up all use of missiles with a range of 500 to 5,500 kilometres.

Both Washington and Moscow withdrew from the Intermediate-Range Nuclear Forces Treaty in 2019, each accusing the other of violations.

Putin said Thursday that Russia will "address the question of further deployment of intermediate and shorter-range missiles based on the actions of the United States and its satellites".