Ukrainian officials troll Russia over the sinking of its flagship missile cruiser: 'Now it's part of the submarine fleet'

• The Moskva, Russia's Black Sea Fleet flagship, sank on Thursday.
• Ukraine says it went down after its guards struck it with anti-ship missiles. Russia denies this.

Ukrainian officials are trolling Russia over the downing of the Moskva guided-missile cruiser, the Russian Black Sea Fleet flagship which sank in the Black Sea on Thursday.

Ukrainian President Volodymyr Zelenskyy thanked "those who have shown that Russian ships can go ... to the bottom only" during a public address on Thursday night, in which he highlighted Kyiv's military successes since Russia's invasion 50 days ago.

Ukraine's minister of defense Oleksii Reznikov took a more mocking tone in a Friday tweet, describing the site of the Moskva's shipwreck as "a worthy diving site."

"We have one more diving spot in the Black Sea now," he added, accompanying the post with an image of a deep-sea diver swimming alongside a turtle.

Ukrainian MP Lesia Vasylenko also poked fun at Russian forces on Thursday, tweeting: "Now it's part of the submarine fleet."

The Moskva, which weighs 12,490 tons, is the biggest Russian warship to be sunk in action since World War II. The ship was believed to have roughly 500 crew, and it's not clear how many of them are casualties of the fire and subsequent sinking.

Russian officials confirmed on Thursday that it had sunk, but denied Ukraine's claim that Ukrainian border guards struck it with Neptune anti-ship missiles,

Both Russia and Ukraine said ammunition had detonated onboard the Moskva, forcing the crew to evacuate, but offered differing explanations for it.

Russia's defense ministry said ammunition exploded due to a fire, the state-run RIA Novosti reported. The ministry said the cruiser ship then sank in "stormy sea conditions."

Ukrainian military officials said on Wednesday that their missile strike caused the explosion and sinking.

US national security advisor Jake Sullivan said on Thursday that he was unable to confirm what caused the explosion.

"They've had to kind of choose between two stories: One story is that it was just incompetence, and the other was that they came under attack, and neither is a particularly good outcome for them," Sullivan told the Economic Club of Washington, DC.