A Russian war ship was struck by Ukrainian forces as they continued to defend the port of Odessa from invading troops, according to Ukraine's navy.
Video footage appeared to show Ukrainian defence forces, based in Odessa, cheering as they exchanged fire with ships in the Black Sea in the early hours of the morning.
One Russian ship - said to be the patrol vessel Vasily Byko - is thought to have been hit as Ukrainian forces defended the country's largest port, Ukraine's navy said on Monday.
'The enemy has retreated again,' it said in a brief statement on Facebook.
While the Ukrainian Armed Forces added: 'Today, March 7, 2022, Navy marine units of the Armed Forces of Ukraine defending the Odessa region hit an enemy ship.'
The apparent attack marked yet another setback for Vladimir Putin as his invasion enters its twelfth day, with the capital of Kyiv still fighting back against invading troops.
A Russian warship - believed to be the patrol vessel Vasily Bykov - is seen smouldering off the coast of Odessa, Ukraine, after being hit by forces defending the city overnight
The Vasily Byko ship was commissioned in December 2018 and is mainly used for protection and monitoring purposes.
The project 22160 patrol vessel, which has a range of 6,000 miles and a maximum speed of 35mph, features two machine guns and two grenade launchers.
The apparent latest hit is another setback for the Russian president as his troops have failed to capture any significant territory nor the capital of Kyiv despite a weekend of heavy fighting.
Russian forces are widely seen as having struggled in the face of Ukrainian military resistance and civil disobedience since entering the country 11 days ago.
The Ukrainian armed forces claimed to have destroyed up to 30 Russian helicopters that had been moved to Chornobaivka airport, near Kherson, overnight and to have retaken the city of Chuhuiv, near Kharkiv, killing two Russian commanders - Lt. Col. Dmitry Safronov, and Lt Col. Denis Glebov - in the process.
Ukraine's ministry of defence claims to have taken out more than 11,000 troops, some 290 tanks, 1,000 armoured personnel carriers, 46 planes, 68 helicopters and 117 artillery pieces as-of Monday morning.
None of those figures has been independently verified. Russia has acknowledged taking losses, but gave a figure of 500 deaths last week and has not updated it since.
The project 22160 patrol ship was commissioned in December 2018 and is mainly used for protection and monitoring purposes
The Vasily Bykov patrol ship, which has a range of 6,000 miles and a maximum speed of 35mph, features two machine guns and two grenade launchers
Ukraine's military estimates that 11,000 Russian soldiers have been killed in fighting along with the loss of 1,000 armoured vehicles, 290 tanks, 68 helicopters, 46 planes and dozens of other piece of hardware.
Independent observers give lower totals, but Franz-Stefan Gady - of the International Institute for Strategic Studies - said the situation is never-the-less 'slowly becoming unsustainable for Russia'.
It comes after President Zelensky accused Russia of a war crime amid plans to bomb the port city of Odessa.
Almost a million people live in Odessa, a cosmopolitan harbour on Ukraine's southern coast with both Ukrainian and Russian speakers and Bulgarian and Jewish minorities.
In a video address, the Ukrainian leader said: 'They are preparing to bomb Odessa.
'Russians have always come to Odessa. They have always felt only warmth in Odessa. Only sincerity. And now what? Bombs against Odessa? Artillery against Odessa? Missiles against Odessa?
'It will be a war crime. It will be a historical crime.'
Analysts have previously said that taking Odessa would be a huge strategic victory and would give Russia a chokehold on Ukraine's economy.
Russia has made progress in southern Ukraine since its invasion 11 days ago, overrunning the city of Kherson and shelling the port of Mariupol, but Odessa has so far been largely spared.
Putin's men renewed their bombardments on Mariupol, Chernihiv, Mykolaiv and Kharkiv this morning as hundreds of civilians tried to evacuate Irpin - on the outskirts of Kyiv - across a destroyed bridge after days of heavy attacks in an attempt to encircle the capital.
But Russian commanders have not significantly advanced their frontline since the city of Kherson and nuclear power plant at Zaporizhzhia were captured last week.
It comes after a military expert suggested that Putin could be 'finished' by the invasion of Ukraine after under-estimating military, social and economic resistance at home and abroad.
Professor Michael Clarke said sending soldiers to take Kyiv was 'massively foolish' and could become a 'peak Putin' moment that leads eventually to his downfall.
Speaking to BBC Radio 4's Westminster Hour, Prof Clarke said 'every day the Ukrainian government is still up and running and standing is a political victory for them and a political defeat for Russia'.
'The Russians can occupy the country at a superficial level. But given that the Ukrainians now hate them - and you are talking about a big country, a physically big country of 45 million people - it is a sheer impossibility that the Russians can control Ukraine in the way that they thought likely or the way Putin thought likely,' he said.
'It's a completely impossible scenario Putin has set his military forces, it's a huge strategic blunder, which incidentally has now become a political crisis in Russia … this is peak Putin. After this Putin is finished.
'We don't know how long it will take, it may be some years or it might actually be quite quick. But there is no way out for this, it is a massive massive mistake on his part.'
Meanwhile, Ukrainian president Volodymyr Zelensky vowed that 'God will not forgive' and Ukraine 'will not forget' the slaughter of civilians by Russian forces, saying a 'day of judgement' is coming for them as Moscow was slammed for
