The threat of intensified attacks on Kyiv also came after Russian authorities accused Ukraine of wounding seven people and damaging about 100 residential buildings with air strikes on Bryansk, a region that borders Ukraine. Authorities in another border region also reported Ukrainian shelling on Thursday.

Kirill Kyrylo, 38, a worker at a Kyiv car repair shop, said he saw three blasts hit an industrial building across the street. The factory was partly destroyed, an AFP journalist at the scene saw on Friday.

Earlier, Ukraine said it hit the Moskva with missiles fired from the coast. Russia did not confirm the attack, saying the ship sank while being towed in stormy seas after a fire caused by an explosion of ammunition. Moscow said more than 500 sailors had been evacuated. There was no independent confirmation of the fate of the crew.

Both sides’ claims have not been independently verified so far. Russian news agencies reported late on Thursday, citing the defence ministry, that the ship sank in rough weather while being towed back to port.

The outcome is an embarrassment for Russia and a win for Ukraine. The ship gained notoriety at the start of the war for a confrontation with a small contingent of Ukrainian guards on Snake Island in the Black Sea who, in colourful terms, reportedly told the Moskva to get lost.

It will also cost Russia militarily. While old – it was commissioned in 1982 – the Moskva was refitted in 2010. It provided a mobile bubble of long-range air defence for the rest of the fleet, as well as command and control systems. Those abilities cannot be easily substituted.

“It is the only class of ship the Russian navy currently has that fields a long-range air defence system,” said Sidharth Kaushal, research fellow for sea power at the Royal United Services Institute, a London-based think tank. “That matters because for the sort of operation the Black Sea Fleet is designed to do, the Moskva has the capability to sit back and create an air defence for the rest of the fleet, and at the same time provide command and control.”

A Western official described the Ukrainian claim of a missile strike on the Moskva as credible, and its loss as a significant blow.

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Although the Moskva had two sister ships, neither is in the Black Sea. They cannot enter it, because under the rules of the 1936 Montreux convention, Turkey is limiting access through the Bosporus strait for Russian naval vessels.

Russia’s navy has played a relatively minor role in the war so far, used primarily as an additional source of cruise missile launchers to attack targets across Ukraine. The Moskva did not have those, but it did carry the anti-ship missiles that made it a spearhead for use against American carrier fleets during the Cold War.

“These ships would completely neutralise the American carrier fleet,” the Russian historian and opposition politician Andrei Zubov wrote on Thursday, in a Facebook post headed “The Inglorious End of the Glory”. He was recalling the words of his late father, an admiral who oversaw construction of the Moskva and other major vessels.

Zubov said his father saw the ship as a deterrent that should never be used in anger. “Thank God, he did not see how the current Russian strategists used his pride,” he said. “It is a big military mistake in itself to use an anti-aircraft deterrent as a ship to provide fire support for an amphibious landing.”

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That is especially the case given the ship’s defence systems and analogue radar were outdated.

Although the Black Sea Fleet has set out as if to attack Odesa multiple times since the war began on February 24, it has not followed through. That is in large part, according to Kaushal, because with a capacity to land 3,000 troops, the amphibious force the fleet can deploy is too small to act without a larger land assault.

That land assault has not yet come because Russian forces have consistently been blocked at Mykolayiv, the gateway to Odesa and Ukraine’s largest Black Sea ports. Had they broken through, the Moskva could have thrown a protective bubble around an amphibious attack, much as it did during the Russia-Georgia war of 2008.

A person close to Russia’s defence ministry said it would be very difficult with or without the Moskva to attack Odesa from the sea, and cast it as more of a symbolic loss. Still, Russia only had a small number of that class of vessel and lacked the shipbuilding capabilities of the Soviet era, the person said.

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Mykolayiv helps explain why the Moskva is unlikely to be replaced for the medium term. Not only does the city have the only shipyard in the former Soviet Union with the capacity to build an aircraft carrier, it also hosts Zorya-Mashproekt, a producer of gas turbine engines for large ships such as the Moskva.

The loss of access to the shipyard and engine maker after Russian President Vladimir Putin’s annexation in 2014 of nearby Crimea has complicated his efforts to modernise the navy and would make it harder to produce another Moskva today. A project to build destroyers of a similar size to the Slava class cruisers has been postponed.

Designs for a next generation aircraft carrier called Storm also remain on paper, in part because without access to the Mykolayiv shipyard, Russia would have to retool one of its own.

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Gas turbine engines matter because they have a better power-to-weight ratio, generating not only the extra power thrust that is needed to propel an 11,490-tonne ship such as the Moskva forward, but the electricity that is increasingly important for complex systems on modern warships, according to Kaushal.

New generation directed-energy weapons and rail guns, in particular, would rely on large amounts of electrical power that only a gas turbine or nuclear powered engine can provide. Russia says it has programmes to develop both.

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The sanctions imposed on Russia for its actions in Ukraine are another complicating factor. Its naval vessels rely on significant quantities of imported parts and technologies from nations that have enacted bans on technology exports.

“Russian glory burns off the coast of Ukraine,” Zubov wrote. “I do not know how many sailors were killed and maimed.”

Bloomberg, Agence France-Presse, Reuters, Associated Press