Baku, May 11, AZERTAC

The United Kingdom has supplied Ukraine with multiple Storm Shadow cruise missiles, giving Ukrainian forces a new long-range strike capability in advance of a highly anticipated counteroffensive against Russian forces, multiple senior Western officials told CNN.

“The UK has previously said that it will supply Ukraine with long-range weapons, this will now include a number of Storm Shadow missiles. The British Government has been clear that this is only in response to Russia’s deliberate targeting of civilian national infrastructure and is a proportionate response,” a Western official told CNN.

The Storm Shadow is a long-range cruise missile with stealth capabilities, jointly developed by the UK and France, which is typically launched from the air. With a firing range in excess of 250km, or 155 miles, it is just short of the 185-mile range capability of the US-made surface-to-surface Army Tactical Missile Systems, or ATACMS, that Ukraine has long asked for.

Critically, the Storm Shadow has the range to strike deep into Russian-held territory in Eastern Ukraine. A Western official told CNN that the UK has received assurances from the Ukrainian government that these missiles will be used only within Ukrainian sovereign territory and not inside Russia. UK officials have made frequent public statements identifying Crimea as Ukrainian sovereign territory, describing it as “illegally annexed.”

UK Defense Secretary Ben Wallace is expected to announce to the House of Commons that the UK is sending Storm Shadow missiles to Ukraine.

The missile is “a real game changer from a range perspective,” a senior US military official told CNN and gives Kyiv a capability it has been requesting since the outset of the war. As CNN has reported, Ukraine’s current maximum range on US-provided weapons is around 49 miles.

The deployment of the missiles comes as Ukrainian forces prepare to launch a counteroffensive intended to retake Kremlin-held territory in the eastern and the southern parts of the country.

Ukrainian President Volodymyr Zelensky said his country still needs “a bit more time” before it launches the counteroffensive, in order to allow some more of the promised Western military aid to arrive in country.

“With [what we have] we can go forward and be successful,” Zelensky told European public service broadcasters in an interview published on Thursday. “But we’d lose a lot of people. I think that’s unacceptable.”

“So we need to wait. We still need a bit more time,” he added. Among the supplies Ukraine is still waiting for are armored vehicles – including tanks – which Zelensky said were “arriving in batches.”