Vladimir Putin's experimental hypersonic rocket unleashed on Ukraine for the first time yesterday could strike any city in Europe in under 20 minutes, it is feared.
Ukraine's air force raised the alarm early Thursday morning that Russia's forces had deployed an intercontinental ballistic missile (ICBM) as security cameras captured the moment multiple warheads rained down over the city of Dnipro.
Putin later revealed the strike was conducted by the 'Oreshnik' - a never-before-seen intermediate-range ballistic missile (IBRM) - in response to Ukraine's use of UK-supplied Storm Shadow rockets to hit targets in Russia's Kursk region.
The weapon is not as powerful or fast as Russia's most fearsome ICBMs like the RS-24 Yars, which is capable of unleashing several separate nuclear warheads anywhere in the US after flying through space at 19,000mph.
But the 'Oreshnik' is still a hypersonic projectile that can fly at 10 times the speed of sound - or around 7,600mph - up to a range of roughly 5,000km, or 3,100 miles, according to Russian military sources.
If the missile was launched from the Kapustin Yar range in Russia's southern Astrakhan region, as it was in yesterday's strike on Ukraine, Putin could still comfortably hit any target in Europe or the UK without having to turn to his most powerful weapons.
Targets in London would go up in flames in under 20 minutes while Berlin further east would have less than 15 minutes before impact.
Russian military analysts also warned that the Oreshnik was certainly nuclear-capable, despite being armed with conventional warheads in the strike on Ukraine.
Russia's ambassador to the UK yesterday declared that Ukraine's use of Storm Shadow missiles on Russian territory means Britain 'is now directly involved in this war'.
'This firing cannot happen without NATO staff, British staff as well,' Andrei Kelin told Sky News this afternoon - a day after British-made rockets battered a military base in Russia's Kursk region.
The Kremlin followed with a statement this morning saying that yesterday's strike was a clear response to the West that Moscow will not tolerate further escalations.
And Vladimir Putin reportedly called a secret meeting with top military brass for this evening after a top British military official insisted the armed forces would be ready to fight tonight if called upon.
The US and UK authorised Kyiv to hit targets on Russian soil with Storm Shadow and ATACMS rockets over the weekend. Ukraine's forces acted quickly, putting them to use in two different attacks in Russia's Bryansk and Kursk regions.
'The main message is that the reckless decisions and actions of Western countries, which produce missiles, supply them to Ukraine and subsequently take part in carrying out strikes on Russian territory, cannot remain without a reaction from the Russian side,' Peskov said.
'We are in no doubt that the current administration in Washington has had the chance to familiarise itself with this announcement and understand it.'
But Western leaders have rebuffed the warning.
Sir Keir Starmer's office said yesterday: 'If (the suspected ICBM strike) is true, clearly this would be another example of grave, reckless and escalatory behaviour from Russia and only serves to strengthen our resolve.'
Swedish Defence Minister Pal Jonson said Stockholm would not be intimidated by Russia's provocations.
'The Russian escalation and provocation that we've been noticing recently is an attempt to scare us from supporting Ukraine, and that will fail. This will not happen,' Jonson told reporters at a joint press conference in Stockholm with his Ukrainian counterpart Rustem Umerov.
The Pentagon said the Oreshnik was based on the RS-26 Frontier - another nuclear-capable missile that experts say blurs the lines between IBRM and ICBM.
Missiles are generally classified as ICBMs if they can strike targets at distances greater than 5,500km, or 3,417 miles.
The RS-26 is said to have a maximum range of roughly 5,800km with a single, lightweight warhead, but has mostly been tested with heavier payloads at much shorter ranges.
Development of the RS-26 was launched in 2008 and its first-ever successful test launch unfolded in May of 2012.
Based on its reported capabilities, the Oreshnik is likely a lighter, less powerful variant of an RS-26 missile designed for strikes at ranges between a few hundred and 5,000km.
US defence officials also confirmed yesterday that Moscow had notified Washington ahead of the strike on Ukraine through nuclear risk reduction channels to avoid triggering early launch warning alarms and a possible response.
Security cameras caught the moment several warheads streaked through the night sky and triggered a series of violent explosions in Dnipro yesterday.
The ferocity, speed and coordinated nature of the salvos suggested the explosions were caused by MIRVs (multiple independently targetable re-entry vehicles) released by the Oreshnik.
MIRVs are typically a feature of nuclear ICBMs designed for full-scale attacks on targets thousands of miles away - one missile can carry multiple warheads that break up and can be guided onto separate targets.
Experts said Putin's use of an advanced hypersonic weapon to deliver a non-nuclear strike on Ukraine was very costly but served to illustrate how Moscow could dramatically escalate the conflict.
Dr Ruth Deyermond, Senior Lecturer in Post-Soviet Security at King's College London, told MailOnline: 'This strike has no obvious military value - they could achieve the same objectives without sacrificing (an ICBM or advanced missile).
'It looks very much as if it's signalling to the West what Russia could do if it chose to - launch a nuclear-armed missile. But it's actually a sign of weakness,' she added.
'The Russian government knows what would happen to it if they did attempt to use any kind of nuclear weapon, so they have to resort to bluffing.'
Dr Mattias Eken, a defence and security analyst at RAND Europe, added: 'The reported range of 700km (to Dnipro) falls short of the typical intercontinental range. Nevertheless, such a strike could have a symbolic value.
'The message that Putin and Russia are trying to send to the West is: we too have missiles that can strike anywhere in the world.
'Particularly after the US allowed ATACMS/Storm Shadow to target Russia, Putin may have felt compelled to demonstrate Russia's ability to use long-range missiles as well.'
