Vladimir Putin’s navy has been “largely neutralised” by Ukrainian coastal defences in its ability to control a swathe of the Black Sea, British defence chiefs said on Tuesday.
They highlighted the reported “first successful use of Western-donated Harpoon anti-ship missiles” to sink a Russian tug.
The attack had thwarted Russian efforts to resupply its forces on Snake Island which has been fiercerly fought over, they added.
In its latest intelligence update, the Ministry of Defence in London said: “On 17 June 2022, Ukrainian forces claimed their first successful use of Western-donated Harpoon anti-ship missiles to engage Russian maritime forces.
“The target of the attack was almost certainly the Russian naval tug Spasatel Vasily Bekh, which was delivering weapons and personnel to Snake Island in the north-western Black Sea.
“The destruction of the Russian vessel on a resupply mission demonstrates the difficulty Russia faces when attempting to support their forces occupying Snake Island.”
The military intelligence briefing added: “This is the latest in a series of Russian vessels, including the cruiser Moskva, to be damaged or destroyed by Ukraine during the conflict.
“Ukrainian coastal defence capability has largely neutralised Russia’s ability to establish sea control and project maritime force in the north-western Black Sea.
“This has undermined the viability of Russia’s original operational design for the invasion, which involved holding the Odesa region at risk from the sea.”
Also known as Zmiinyi Island, Snake Island lies in the north-western Black Sea, some 30 miles from the Ukrainian coast and 180 miles west of annexed Crimea.
It became a symbol of defiant Ukrainian resistance in the face of overwhelming Russian power at the start of Mr Putin’s invasion on February 24.
Around a dozen Ukrainian soldiers were feared to have been obliterated by a Russian bombardment after reportedly refusing to surrender and telling one of its warships to “go to hell”.
They were awarded posthumous bravery honours by Ukraine’s president Volodymyr Zelensky.
Defence chiefs in Britain and other countries in the West are engaged in an information war against Russia, as part of the conflict in Ukraine, so their intelligence briefings and claims need to be treated in that context.
However, the Kremlin’s claims need to be treated with even more caution given that it does not even accept Mr Putin has unleashed a war in Ukraine and its denials of war crimes and killing thousands of civilians are very much at odds with widespread reports from the conflict zone.
Meanwhile, Russia has warned NATO member Lithuania that unless it quickly lifts a new ban on the transit of goods to Russia’s Kaliningrad exclave on the Baltic Sea, then Moscow will take undisclosed measures to defend its national interests.
Ukraine acknowledged on Tuesday difficulties in fighting in its east as Russian forces regrouped to launch a fresh onslaught on the city of Severodonetsk in the Luhansk province of the Donbas region.
Serhiy Gaidai, governor of Luhansk, said Russian forces had gained some territory on Monday though it was relatively quiet overnight.
“It’s a calm before the storm,” he said.
Mr Zelensky predicted the Kremlin would step up attacks ahead of the EU summit on Thursday and Friday. He was defiant in a late Monday address to the nation, while also referring to “difficult” fighting in Luhansk for Severodonetsk and its sister city, Lysychansk.
“We are defending Lysychansk, Severodonetsk, this whole area, the most difficult one. We have the most difficult fighting there,” he said.
“But we have our strong guys and girls there.”
Mr Gaidai said Russian forces controlled most of Severodonetsk, apart from the Azot chemical plant, where more than 500 civilians, including 38 children, have been sheltering for weeks.
The road connecting Severodonetsk and Lysychansk to the city of Bakhmut was under constant shell fire, he said.
Rodion Miroshnik, ambassador to Russia of the self-styled Luhansk People’s Republic, said its forces were “moving from the south towards Lysychansk” with firefights erupting in a number of towns.
“The hours to come should bring considerable changes to the balance of forces in the area,” he said on Telegram.
Mr Putin sent tens of thousands of troops into Ukraine on February 24 in what Moscow called a “special operation” to degrade its military capabilities and root out what it calls dangerous nationalists.
It has introduced a law making the spread of “knowingly fake” information or reporting that could discredit the Russian military an offence.
Dmitry Muratov, the co-winner of the 2021 Nobel Peace Prize and editor of independent Russian newspaper Novaya Gazeta, auctioned off his Nobel medal for a record $103.5 million (£84 million) to aid children displaced by the war.
His paper, fiercely critical of Mr Putin, suspended operations in Russia in March after warnings over its coverage of the war.
The war has entered a brutal attritional phase in recent weeks, with Russian forces concentrating on Ukrainian-controlled parts of the Donbas, which Russia claims on behalf of separatists.
Ukrainian officials reported three civilian deaths in Russian shelling in the Donetsk region on Monday and another three in shelling in the Kharkiv region.
In Odesa, Ukraine’s biggest Black Sea port, which is blockaded by the Russian navy, a Russian missile destroyed a food warehouse on Monday, Ukraine’s military said.
The United States and its European allies have provided weapons and financial assistance to Ukraine but avoided direct involvement in the conflict. Some citizens from Britain, the US and other nations, however, have volunteered to fight for Ukraine.
On Monday, the Kremlin said two Americans detained in Ukraine were mercenaries not covered by the Geneva convention who should face responsibility for their actions.
Kremlin spokesman Dmitry Peskov’s comments were the first formal acknowledgment that the two, identified in US reports as Andy Huynh, 27, and Alexander Drueke, 39, were being held.
A US State Department spokesperson said they had been in touch with Russian authorities regarding any American citizens who may have been captured.
“We call on the Russian government – as well as its proxies – to live up to their international obligations in their treatment of any individual, including those captured fighting in Ukraine,” it said.
This month, a separatist court in the Donbas sentenced Britons Aiden Aslin and Shaun Pinner, and Moroccan Brahim Saaudun, to death after they were caught fighting for Ukraine.
