Russian President Vladimir Putin has dramatically escalated the war in Ukraine by launching a long-range ballistic missile, Downing Street has signalled.

No 10 confirmed a ballistic missile with a range of several thousand kilometres had been fired on the city of Dnipro, after reports from Ukraine about a new weapon entering the arena of war.

Kyiv had initially said an intercontinental ballistic missile (ICBM) had been launched, a claim which Western officials cast doubt on.

The Prime Minister’s official spokesman was cautious not to use this term, instead telling reporters: “My understanding is that it is the first time that Russia has used a ballistic missile in Ukraine with a range of several thousand kilometres.”

No 10 said it was “easily an example of escalatory behaviour from Russia” when asked whether the Government believed the Kremlin had ramped up the conflict with the attack.

But the Prime Minister’s spokesman added it “only serves to strengthen our resolve and to ensure that Ukraine has what it needs to act in self-defence against Russia’s reckless and illegal invasion”.

The missile’s range far outstrips that of newly authorised US and British supplied weapons which are reportedly now in use in the war, as Kyiv seeks to fire on military bases deep in Russian territory.

Russia’s military claims it has shot down two British-made Storm Shadow missiles, following reports that debris from the weapons had been discovered in the country’s Kursk region, which borders Ukraine.

American-supplied ATACMS missiles have been fired at Russia following authorisation by US President Joe Biden.

Defence Secretary John Healey earlier revealed to a committee of MPs that the UK had expected Russia to begin using long-range ballistic missiles for some time.

“There are unconfirmed but media reports today of Russia firing a new ballistic missile into Ukraine which we know they have been preparing for months,” he said at the Commons Defence Committee.

Mr Healey had warned Ukraine faces a “serious moment” in its defence against Mr Putin’s invasion, and refused to be drawn into confirming reports the war-torn nation has launched British-supplied long-range missiles at its foe.

“It risks both operational security and in the end the only one that benefits from such a public debate is President Putin,” the Defence Secretary told MPs.

Battle lines in Ukraine are now “less stable than at any time since the early days of the full-scale Russian invasion”, Mr Healey said, citing British intelligence.

Speaking at the same time, Prime Minister Sir Keir Starmer told the House of Commons the UK “will not be deterred or distracted by reckless threats”, in reference to Mr Putin lowering the threshold for using his nuclear arsenal.

This was widely seen as a response to Mr Biden’s announcement that he would give Ukraine permission to use US-made long-range ATACMS missiles.

Sir Keir also insisted that all the UK’s support for Kyiv was “in accordance with international law” and “always for self-defence”.