Factbox-What is Russia's 'Oreshnik' missile?

President Vladimir Putin said Russia had struck Ukraine with a new hypersonic medium-range ballistic missile in response to Kyiv's use of U.S. and British missiles against Russia.

What is the "Oreshnik" (Hazel tree)?

WHAT DID PUTIN SAY?

Putin said on Thursday that the Ukraine war was escalating towards a global conflict after the United States and Britain allowed Ukraine to strike deeper into Russia with their missiles, and warned the West that Moscow could strike back.

In direct response to Ukraine's use of U.S. and British missiles on Nov. 21, he said Russia had launched an "Oreshnik", one of its newest intermediate-range missiles, at a defence enterprise in the Ukrainian city of Dnipro.

The city is home to the missile and space rocket company Pivdenmash, known as Yuzhmash to Russians.

WHAT IS THE MISSILE?

Putin said "Oreshnik" was a hypersonic ballistic missile.

He said it travelled at 10 times the speed of sound and so could not be intercepted. Russian sources said the range was 5,000 km (3,100 miles), allowing Russia to strike most of Europe and the west coast of the United States.

It appears to have multiple independently targetable re-entry vehicles: separate warheads able to hit different targets.

Anatoly Matviychuk, a Russian military expert, said it could carry six to eight conventional or nuclear warheads, and was probably already in service, according to Yuri Podolyaka, a prominent Ukrainian-born, pro-Russian military blogger.

The Pentagon said the missile that Russia fired was based on the "RS-26 Rubezh" intercontinental ballistic missile (ICBM).

It said the U.S. had been notified of the launch through nuclear risk reduction channels.

WHAT DID UKRAINE SAY?

Ukraine's air force said Russia had fired an ICBM at Dnipro, though the United States said that was incorrect. ICBMs are defined as having a range greater than 5,500 km (3,400 miles).

President Volodymyr Zelenskiy said that a Russian attack with a new type of ballistic missile was a "clear and severe escalation" and called for worldwide condemnation.

WHAT IS THE RS-26?

The RS-26 is a solid-fuelled, road-mobile ballistic missile that entered development in 2008.

The United States formally withdrew from the landmark 1987 Intermediate-Range Nuclear Forces (INF) Treaty with Russia in 2019 after saying that Moscow was violating the accord, an accusation the Kremlin denied.

The United States said at the time that Russia was developing a ground-based cruise missile (known as 9M729 in Russia) that was distinct from the RS-26.