Russian Black Sea fleet's flagship Moskva has sunk, the Russian state media and defence ministry has confirmed. This is a serious blow to Russia irrespective of the reason behind Moskva journey into the depths of the Black Sea.

The Russian defence ministry claims that ammunition on Moskva exploded due to an unexplained fire on the naval vessel. Russia's defence ministry added another statement claiming that fire onboard had been contained and that the warship would be towed back to a safe port.

But Moskva didn't make it till the port. After initially claiming that the Moskva was still afloat, Russia's defence ministry has now confirmed that whilst being towed to the port she sank.

"While being towed... towards the destined port, the vessel lost its balance due to damage sustained in the hull as fire broke out after ammunition exploded. Given the choppy seas, the vessel sank," reports Russia's news agency TASS.

The 510-crew missile cruiser was the symbol of Russian naval pride and military might.

The Ukrainians have claimed responsibility for the fire on Moskva. The Ukrainians say that they attacked the warship with Ukrainian-made Neptune missiles.

Russians have so far refused to give any explanation for the fire on Moskva. Both the claims may be true. In other words, a scenario is possible where Ukrainian missiles stuck the naval vessel, and then ammunition on the vessel began exploding as a result.

According to reports, Kremlin Spokesman Dmitry Peskov repeatedly declined to answer questions about the fate of the Moskva during a daily media call.

"This is a topic for the Ministry of Defense, I can't say anything," he said.

Pentagon's Press Secretary John Kirby said, "We're not quite exactly sure what happened here. We do assess that there was an explosion, at least one explosion on this cruiser. A fairly major one at that, that has caused extensive damage to the ship".

Regardless of the cause, this is a massive loss for the Russians, tactically, symbolically and emotionally.

This will have serious implications for the morale of Ukrainians on the battlefield. It will boost their confidence and influence the intensity with which they fight on the battlefield.

There are obvious tactical implications as well, even if one keeps the issue of morale aside. Moskva was providing air cover for other ships, which may now be more at risk of aerial attack.

Beyond the tactical implications, the larger issue is that of symbolism. The Moskva has for long been a symbol of Russian military might. No matter what the cause, the sinking of Moskva is terrible news for Kremlin and delightful news for Kyiv.

Ironically, the Moskva was originally built in Ukraine during the Soviet era. She entered service in the early 1980s and was originally named 'The Slava'. She has been upgraded to keep up with the changing technology. In 1995, she was modernised and renamed Moskva. She re-entered service in 1998.

She is a Slava class cruiser and is the third-largest naval vessel in Russia's active fleet, making her one of the most heavily defended assets. The vessel is supposed to be equipped with a triple-tier air defence system.

Along with medium- and short-range defences, she is equipped with close-in weapon systems (CIWS). In other words, she should have a 360-degree anti-air defence coverage. The CIWS system fires 5,000 rounds a minute, which creates a wall of flak around the warship and acts as its last line of defence.

If the Ukrainians did indeed succeed in striking the warship with Neptune missiles, it indicates that Russia's surface fleet hasn't undergone the modernisation it is supposed to, or it had engineering issues. This will make importers of Russian military technology consider if they should diversify the source of their military technology and equipment.

The Ukrainian Neptune missiles are a category of anti-ship cruise missiles. They have a range of around 280 km on paper and weigh 870 kg. It is armed with a warhead of high explosive fragmentations. It was developed by Ukraine after Russia's annexation of Crimea.

With both Russia and Ukraine giving different versions, precisely what led to the incident remains unknown. Given that Moscow tried to keep the development under wraps, it can be safely assumed that neither version makes Russia look good. If it resulted from an accident, it shows a lack of preparedness on Russia's part. If it was a result of a Ukrainian missile strike, it signals Russian incompetence.

Only the loss of the Kuznetsov (Russia's lone aircraft carrier) or a submarine would inflict a more serious blow to the Russian Navy's reputation.