KYIV, Ukraine — Ukraine has sunk or disabled a third of all Russian warships in the Black Sea in just over two years of war, the navy spokesman said Tuesday, a heavy blow to Moscow’s military capability.

Ukraine’s Navy spokesman Dmytro Pletenchuk told The Associated Press that the latest strike on Saturday night hit the Russian amphibious landing ship Kostiantyn Olshansky that was resting in dock in Sevastopol in Russia-occupied Crimea. The ship was part of the Ukrainian navy before Russia captured it while annexing the Black Sea peninsula in 2014.

Previous Strikes and Damage

Pletenchuk has previously announced that two other landing ships of the same type, Azov and Yamal, also were damaged in Saturday’s strike along with the Ivan Khurs intelligence ship.

He told the AP that the weekend attack, which was launched with Ukraine-built Neptune missiles, also hit Sevastopol port facilities and an oil depot.

Russian authorities reported a massive Ukrainian attack on Sevastopol over the weekend but didn’t acknowledge any damage to the fleet.

Impact on Russian Fleet

Pletenchuk said that with the latest attack, a third of all warships that Russian had in the Black Sea before the war have been destroyed or disabled. At the same time, he acknowledged that just two of about a dozen of Russian missile carrying warships have been sunk and pledged that Ukraine will continue the strikes.

“Our ultimate goal is complete absence of military ships of the so-called Russian Federation in the Azov and Black Sea regions,” Pletenchuk told the AP.

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Boost for Kyiv

Successful Ukrainian drone and missile strikes have provided a major morale boost for Kyiv at a time when its undermanned and under-gunned forces are facing Russian attacks along the more than 1,000-kilometer (600-mile) front line.

Challenging Russia’s naval superiority also has helped create more favorable conditions for Ukrainian grain exports and other shipments from the country’s Black Sea ports.

Russian Response

Moscow officials have kept mum on most of Ukrainian claims, but previous navy losses have been confirmed by Russian military bloggers and media who have harshly criticized the military brass for its slow and sloppy response to the threat.

Earlier this month, Russian media reported that the navy chief, Adm. Nikolai Yevmenov, had been fired and replaced with Adm. Alexander Moiseyev, the commander of Russia’s Northern Fleet. The Kremlin hasn’t yet announced the reshuffle, but last week Moiseyev was presented as the new acting navy chief during a ceremony at a Russian naval base.