Vladimir Putin's prized £275million submarine is obliterated by Ukraine during a devastating missile strike on naval base in Russian-occupied Crimea

Ukraine has obliterated a £275million submarine prized by Putin in a missile strike on Russian-occupied Crimea.

The kilo-class vessel, named Rostov-on-Don, was hit during a huge missile barrage, Ukrainian forces confirmed.

The submarine, used to fire calibre class missiles into Ukraine, had been repaired from previous damage after being targeted in September last year.

Dramatic pictures last year showed a huge hole blown into the sub during Ukrainian strikes last year. 

It was due to return to service when it was sunk by Ukrainian forces in Sevastopol on Friday night.

A prized kilo-class Russian submarine has been sunk by a missile strike, Ukrainian forces confirmed

The Rostov vessel was previously targeted by Ukrainian forces last September, when a huge hole was blown into its body

The sub was repaired and was due to return to service when it was struck again and sunk during sea trials

The strike is also believed to have hit Russian ultra-modern S400 air defence systems (pictured operating on Friday night)

The vessel was undertaking sea trials when it was struck by deadly US-built ATACMAS missiles.

Russian ultra-modern S-400 air systems worth £2billion were also 'significantly damaged' in the attack, the Sun reported.

The downing of the prized sub marks a large coup for Zelenskyy's forces, which also confirmed that the attack had hit four launchers for Putin's Triumf air defence system.

It comes after Russia suffered another major setback as two of its £170million warships were hit in a strike on Sevastopol.

The Yamal and the Azov landing ships were both struck in an onslaught of the Black Sea port.

Footage shows the major strikes on Sevastopol during the night. The strike comes days after Admiral Alexander Moiseev, 61, was made commander-in-chief of the Russian navy after the dictator abruptly fired previous incumbent

The Yamal and the Azov (pictured) landing ships, each worth £170 million, were both hit in the overnight onslaught while in Black Sea naval port Sevastopol, according to reports

The Yamal a Ropucha class landing ships would have a normal crew of 98

Image of the attack that took place last night on the city of Sevastopol, believed to be the heaviest bombardment of the city to date

British-made Storm Shadow missiles were thought to have been used in what was the largest bombardment of the Crimean port to date. 

Ukrainian Telegram channel Pravda Gerashchenko announced: 'In occupied Sevastopol, the Ukrainian Defence Forces successfully hit the large landing ships Yamal and Azov, the Communications Centre and several infrastructure facilities of the Russian Black Sea Fleet.'

Both vessels are 369ft in length and were built in Gdansk, Poland during the Soviet era, but have since been modernised, and were believed to have a crew of 98 and 87 people respectively. 

Complex plans are also underway to destroy a £3billion bridge joining annexed Crimea to Russia.