Ukraine has claimed a 'significant' victory against Putin's Black Sea forces after pounding the Russian garrison on the strategic Snake Island.
The southern operational command said it had 'aimed strikes with the use of various forces' on the island, causing major losses to Kremlin troops.
Satellite images show the damage wrought by Kyiv forces, with burning vegetation and a tower destroyed in the fight for the island.
The Russian Pantsir anti-aircraft system, a radar station and vehicles were all damaged in the attacks on the island which has been a major battleground throughout the war.
It is just the latest blow for Putin who has suffered 'extraordinary' losses with pro-Russian separatists in Donetsk losing 55 per cent of its troops, British intelligence said today.
The Ministry of Defence said Russia's outdated weapons and equipment have hampered their success, and the Kremlin will now have to deploy reserve units to the Donbas to make up for the losses.
The 100-acre Snake Island outpost has proved to be a valuable strategic position for both sides, sitting some 80 miles off Ukraine's southern coastline in the Black Sea.
Russia seized the island early in the war and has largely managed to maintain control of it, but its forces there have been subject to bombing raids ever since.
Snake Island is seen in an aerial photo on June 17 before Ukraine carried out a series of strikes on the strategic outpost
By June 20, Ukraine had caused serious damage, with satellite imagery showing devastated regions
The southern operational command said it had 'aimed strikes with the use of various forces' on the island, pictured on June 17
The Russian Pantsir anti-aircraft system, a radar station and vehicles were all damaged in the attacks (pictured on June 20)
In February, Ukrainian border guard Roman Hrybov on Snake Island famously radioed 'Russian warship, go f*** yourself' to Russian officers aboard the Moskva.
Hrybov and his crew were thought dead after the Moskva bombarded the island with artillery fire, but they miraculously survived and were given awards upon being returned to Ukrainian soil in a prisoner transfer last month.
The latest strikes come days after a Russian navy tugboat transporting crew and armaments to Snake Island was destroyed in the Black Sea just with two Harpoon missiles.
It was the first time Kyiv claimed to hit a Russian vessel with the Western-supplied anti-ship rockets.
Ukraine's Armed Forces Strategic Communications Directorate showed the anti-ship missile striking the tug Vasily Bekh at 4am as it delivered soldiers, weapons, and ammunition to hotly-contested island.
A Ukrainian serviceman on a position in the city of Severodonetsk of Luhansk area
A Ukrainian service member with a dog observes in the industrial area of the city of Sievierodonetsk
The city of Severodonetsk and its surroundings witnessed heavy fighting in recent days
The Housing and Communal College building damaged in recent shelling in Kharkiv, Ukraine, on Tuesday
Russian Black Sea Navy the tug Vasily Bekh was reportedly hit by an anti-ship missile while it was delivering troops and weapons to Snake Island
Its Tor anti air missile system failed to halt the strike but the tug remained afloat and was being evacuated for repairs after sustaining significant damage
Its Tor anti air missile system failed to halt the strike but the tug remained afloat and was being evacuated for repairs after sustaining significant damage. Pictured: The Vasily Bekh in happier times
Ukrainian sources later claimed ten sailors on the tug were missing presumed dead, and 23 wounded. The crew number was put at 33.
Harpoon missiles are anti-ship ballistics that were first developed by the US and now manufactured by Boeing.
The US has sent Harpoon missiles to Ukraine while the UK and Denmark have said they will consider sending the ballistics. It was not immediately clear where these ballistics had come from.
The Snake Island battle comes as a Ukrainian kamikaze drone today ploughed into a major oil refinery inside Russian territory, sparking a huge fireball explosion.
Footage shows the unmanned aerial vehicle (UAV) flying at a low-level height towards the Novoshakhtinsk oil refinery in the Rostov region, which borders Ukraine.
Video then shows the drone striking the oil refinery, causing a massive explosion which was heard ten miles away.
Flames engulfed the building and black smoke poured from the key strategic facilities, located some four miles from the pro-Putin puppet state Luhansk People's Republic in Ukraine.
Russian workers, who unwittingly filmed the drone strike, were heard laughing at the sight of the drone as it flew close to them - but they panicked and swore repeatedly after it struck the refinery, with one shouting 'f*****g run away'.
The unmanned aerial vehicle (UAV) was seen flying at a low-level height towards the Novoshakhtinsk oil refinery in the Rostov region, which borders Ukraine. Video then shows the drone striking the oil refinery, causing a massive explosion which was heard ten miles away
Video shows the drone striking the oil refinery (left, circled), causing a massive explosion (right)
Footage from the scene shows firefighters battling to contain the blaze, as plumes of black smoke billowed into the air.
Russian air defences failed to pick up the incoming drone, initially reported to be Turkish-made Bayraktar, but later said to be a Ukrainian UAV PD-1 or PD-2.
Some reports said the visible drone was one of two which targeted the facility.
It caused the explosion while another lay on the ground between two giant oil tanks.
Footage from the scene shows firefighters battling to contain the blaze, as plumes of black smoke billowed into the air
Workers nearby are heard on a video as they watched the approaching military drone.
Initially they were relaxed as it flew close to them but they swore repeatedly as the unmanned craft struck the oil plant triggering a huge explosion.
One is heard saying: 'It came from the Ukrainian side, didn't it?'
Another answers: 'Yes, yes.'
One asks: 'Do we stop work?'
Another replies: 'The plant is on fire. F***ing run away.'
Novoshakhtinsk refinery is reportedly the largest oil supplier in southern Russia.
It is owned by the Research and Design Institute of Oil and Gas Peton, from Ufa, and previously belonged to offshore companies linked to Viktor Medvedchuk, a close ally of Putin detained by the Kyiv authorities, as had been suggested.
Flames engulfed the building and black smoke poured from the key strategic facilities, located some four miles from the pro-Putin puppet state Luhansk People's Republic in Ukraine
Novoshakhtinsk refinery (file image) is reportedly the largest oil supplier in southern Russia. It is owned by the Research and Design Institute of Oil and Gas Peton, from Ufa, and previously belonged to offshore companies linked to Viktor Medvedchuk, a close ally of Putin detained by the Kyiv authorities, as had been suggested
The press service of the regional head office of the Russian Ministry of Emergency Situations acknowledged the blaze. It claimed there was no threat of the fire spreading and said there were no casualties.
The explosion comes as Russian casualties have risen to 55 per cent of the original strength of the Donetsk People's Republic forces, Britain said.
Figures published by the DPR showed that by June 16, 2,128 military personnel had been killed in action, with 8,897 wounded since the beginning of 2022, the British defence ministry said in a daily Twitter update.
Russian authorities have not released the tally of military casualties in Ukraine since 25 March, it added.
The 100-acre outpost has proved to be a valuable strategic position, sitting some 80 miles off Ukraine's southern coastline in the Black Sea
The MoD said: 'The DPR casualty rate is equivalent to around 55 per cent of its original force, which highlights the extraordinary attrition Russian and pro-Russian forces are suffering in the Donbas.
It is highly likely that DPR forces are equipped with outdated weapons and equipment.
'On both sides, the ability to generate and deploy reserve units to the front is likely becoming increasingly critical to the outcome of the war.'
Russian forces and separatists in east Ukraine made advances on Tuesday, pushing towards Lysychansk city, the Ukrainian forces' main bastion in the Donbas.
In some of the bloodiest fighting in Europe since World War Two, Russia has made slow progress in the Donbas since April in a conflict that has cost thousands of soldiers' lives on both sides.
Some of the fighting has spanned the Siverskyi Donets river that curls through the Donbas, with Russian forces mainly on the east bank and Ukrainian forces mainly on the west.
But Ukrainian troops - and an estimated 500 civilians - are reportedly still holding out at a chemical plant in the east bank city of Sievierodonetsk.
The governor of Luhansk province, Serhiy Gaidai, said Russians were advancing towards Lysychansk, attacking the buildings of police, state security and prosecutors, taking settlements and attacking the city with aircraft.
Oleskiy Arestovych, an adviser to Zelenskiy, said Russian forces could cut off Lysychansk and Sievierodonetsk from Ukrainian-held territory.
'The threat of a tactical Russian victory is there, but they haven't done it yet,' he said in an online video.
Attacks have picked up in the Kharkiv region in the northeast, with at least 15 civilians killed by Russian shelling, its governor said on Tuesday.
'Russian forces are now hitting the city of Kharkiv in the same way that they previously were hitting Mariupol - with the aim of terrorising the population,' Arestovych said. 'The idea is to create one big problem to distract us.'
Both Russia and Ukraine are today holding a day of commemoration to mark the anniversary of Hitler's invasion of the Soviet Union in 1941.
June 22 is a significant date in Russia - the 'Day of Remembrance and Sorrow' - marking when Hitler's Nazi Germany forces invaded the Soviet Union in World War Two.
A woman walks in front of a residential building that was damaged during the Russian attack, in Borodyanka
The Housing and Communal College building is damaged in recent shelling in Kharkiv
A child rides on a swing in front of a residential building that was damaged during the Russian attacks
It is also commemorated in Ukraine and neighbouring Belarus, then part of the Soviet Union. The war there lasted 1,418 days from June 22, 1941, and historians estimate about 27 million Soviet soldiers and civilians were killed.
Putin is due to lay flowers to honour the dead.
To mark the anniversary, the Russian defence ministry on Wednesday released documents dating back to the beginning of World War Two purporting to show Germany intended to claim the Soviet army was bombing churches and cemeteries to justify its invasion.
'Just as nowadays, in 1941, the Nazis prepared provocations in advance to discredit our state,' Russia's defence ministry said.
Ukraine said Wednesday that the eastern industrial city of Severodonetsk was 'hell' as Russian forces moved to encircle two key cities in the Donbas where Moscow has concentrated its military efforts.
'For four months all our positions have been under fire from everything - and I just want to emphasis this - from all the weapons that the Russian army has,' the Lugansk regional governor Sergiy Gaiday said in a statement on social media.
'It's just hell out there,' he added, referring to Severodonetsk, which has been heavily shelled for weeks by Russian forces who are trying to gain complete control of the city.
'Our boys are holding their positions and will continue to hold on as long as necessary,' he added.
Russian forces in recent days have made territorial gains south of Severodonetsk and moved closer to its sister city of Lysychansk separated by the river Donets.
Gaiday said Russian forces were 'trying to encircle the city' of Lysychansk but that Ukrainian forces still controlled the city.
'Lysychansk is being heavily shelled with heavy calibre weapons,' he added, describing 'colossal destruction.'
Gaiday said that people were steadily being evacuated from Lysychansk and that 'we are slowly taking people out.'
In Severodonetsk however, hundreds of civilians seeking refuge in the Azot chemical plant were unable to leave due to the scale of the fighting, he said.
'Evacuation is possible if there is an agreement at the highest level, if there will be a ceasefire and a clearly defined route,' Gaiday said.