According to media reports, the US confirmed on Friday that Ukrainian forces sank the Russian ship Moskva with at least one Neptune missile.
The confirmation from a US defense official comes after both Russia and Ukraine said that the ship was damaged when it exploded.
Russian officials said that the crew had been evacuated and that the ammunition exploded due to a fire on board.
The Ukrainian officials said the border guards hit the vessel with Neptune anti-ship missiles, causing serious damage.
The Pentagon's assessment was based on recent intelligence. It is in line with the Ukrainian version of events. The unnamed defense official told media that there were likely casualties.
According to The Washington Post, the Pentagon observed some Russian sailors evacuate a burning ship. The Wall Street Journal reported that the ship sank in the Black Sea as it was being towed to Crimea for repairs.
The attack is a blow to the Russian people. The Journal reported that the warship was a key factor in Russia's naval strategy in the Black Sea. Russia will not be able to replace the loss according to a Pentagon official.
Russian ships have been firing at Ukrainian cities from the Black Sea. The defense official told The Post that Russia has two other similar ships, but they are not based in the Black Sea. Russian warships will not be able to take part in any amphibious assault near Odessa without being hit by more Ukrainian Neptune missiles.
The Moskva made headlines in February after an apparent audio exchange between the vessel and Ukrainian island border guards went viral. The Ukrainian guards could be heard saying "Go fuck yourselves" when the fleet was told to surrender.
The downed Moskva was referred to by Ukrainian officials as a "worthy diving site" and a "submarine fleet" following the reported sinking.