Ukraine has used longer-range Storm Shadow missiles against targets in Russia for the first time, the BBC understands.
The move follows US President Joe Biden giving the green light to Ukraine Atacms missiles are supplied by Washington to attack in Russia, causing a furious response from the Kremlin.
Ukraine has used two missiles for a month, but only against targets in Russian-controlled territory.
What is Storm Shadow?
The Storm Shadow is an Anglo-French cruise missile with a maximum range of about 250km (155 miles). The French call it Scalp.
It was launched from an aircraft, then flew at the speed of sound, hugging the terrain, before descending and detonating a high-altitude warhead.
Storm Shadow – made by the manufacturer MBDA – is considered an ideal weapon for penetrating hardened bunkers and ammunition stores, such as those used by Russia in the war against Ukraine.
But each missile costs almost US$1m (£767,000), so it is usually launched as part of a carefully planned, cheaper drone fleet, sent forward to confuse and reduce enemy air defences, as Russia did to Ukraine.
They have been used to great effect, attacking Russia’s Black Sea naval headquarters in Sevastopol and making all of Crimea unsafe for the Russian navy.
Justin Crump, a military analyst, former British Army officer and CEO of Sibylline consultancy, said Storm Shadow is a very effective weapon for Ukraine, precisely hitting well-protected targets in occupied territory.
“It’s no surprise that Kyiv has lobbied for its use in Russia, especially to target airfields used to launch cruise bomb attacks that have recently hampered Ukraine’s front-line efforts,” he said.
Has the UK changed its rules?
Britain has been supplying Ukraine with Storm Shadow missiles for months but, like the US, has refused to allow Kyiv to use them to launch attacks in Russia.
But that changed after the Biden administration updated its rules, allowing the same Atacms missiles to be used outside Ukraine’s borders.
On Wednesday, it was confirmed that Ukraine used the British-supplied Storm Shadow missile against targets in Russia for the first time.
The Ministry of Defense has not commented publicly. But the British government is known to support allowing Ukraine more freedom to use its missiles as it sees fit, even if it follows US policy.
Why does Ukraine want Storm Shadow?
The most immediate priority is to suppress the expected Russian counterattack on Ukrainian positions in the Kursk region in western Russia.
But Ukrainian cities and front lines are also bombed daily from Russia.
Many missiles and rocket bombs that caused damage to military positions, apartment blocks and hospitals were launched by Russian aircraft far away in Russia itself.
Kyiv said it was not allowed to attack the base from which the attack was launched similar to this war with one hand tied behind the back.
Ukraine has its own long-range drone program, innovative and effective.
Sometimes, these drone strikes catch Russians off guard and reach hundreds of kilometers inside Russia.
But it can only carry a small payload and can generally be detected and intercepted.
Kyiv says that to repel Russian airstrikes, it needs long-range missiles, including the Storm Shadow.
The US decision to allow the use of its own long-range missiles is also intended to help Ukraine defend the small part of Russian territory it currently controls in the Kursk region. A major attack by Russian and North Korean forces is expected.
With the green light to use long-range missiles, airfields and major logistics centers inside Russia are also on Ukrainian territory.
How different is Storm Shadow?
Kyiv has been calling for the use of long-range Western missiles in Russia for a long time, so Moscow has been cautious.
It has moved the bombers, missiles and some of the infrastructure that keeps them going further, away from the border with Ukraine and beyond the range of Storm Shadow.
There is skepticism among Western officials that Storm Shadow and American Atacms will be decisive.
However, the Institute for the Study of War think tank (ISW) has identified around 225 Russian bases that will be in some of the Storm Shadows fired from Ukraine.
And Sibylline’s Justin Crump said that while Russia’s air defenses have developed to counter the Storm Shadow threat in Ukraine, this task will be made more difficult by the Moscow region that is now vulnerable to attack.
“This will make military logistics, command and control, and air support more difficult to deliver, and even if Russian aircraft withdraw further from the Ukrainian border to avoid the missile threat, they will suffer an increase in time and cost of each sortie to the front line.”
Matthew Savill, director of military science in the Russian think tank, believes that it can also pose a dilemma for Russia where to position the air defense, which can make it easier for Ukrainian drones to pass.
Ultimately though, said Savill, Storm Shadow is believed to turn the tide. Ukraine does not have many missiles, and the UK has very few to give.
What did Putin say about Western involvement in the use of Storm Shadow missiles in Ukraine?
One of the reasons President Putin sees the use of Storm Shadow as an escalation is his belief that Ukrainian forces cannot use long-range missile systems without the help of Western specialists.
He previously told reporters in Russia that “only soldiers of NATO countries can go on a flight mission to this missile system,” adding that Kyiv also relies on satellite intelligence provided by the West to select targets.
Manufacturer MBDA declined to comment on the claims when approached by the BBC, referring inquiries to the UK Ministry of Defence.
A spokesman for Ukraine’s presidential office also declined to address Putin’s accusations, saying he could not comment on “specific technical details of weapons”.
Justin Crump doubted Putin’s claim, telling the BBC that “the claim is true, so Russia will make it more clear when the weapon is first supplied, and when it conducts a successful and influential operation against, for example, the Black Sea Fleet HQ. in the occupied Crimea” .
“Missiles are available for export sales; is Russia seriously saying that the buyer must have a NATO/British team to program and use the missiles? That should be buried deep in the brochure print, and it will not make for an attractive prospect,” he said.