Russia says flagship of its Black Sea fleet has sunk

The big picture: Ukraine claimed it struck the 610-foot Soviet-era vessel with cruise missiles on Wednesday.

• Russia's defense ministry claimed the fire on the cruiser started after the detonation of ammunition on board.
• A senior U.S. defense official said earlier Thursday that the Moskva had experienced "significant damage" and was heading east while continuing to battle a fire on the cruiser. The official could not confirm the cause of the explosion.
• It's unknown if there were any casualties. Russia's defense ministry said it evacuated the ship's approximately 500 crew members on Wednesday.

Between the lines: The Moskva was involved in one of the famous early exchanges of the war, when Ukrainian border guards defending Snake Island told the warship to "go f*ck yourself" in response to a call to surrender.