Russia confirmed that the missile cruiser Moskva - the main warship of its fleet in the Black Sea - sank when towed to port, after it said that a fire broke out after its ammunition exploded.
Ukraine says Moskva was hit by a missile strike launched by its forces from the coast that split the hull of the Soviet-era ship.
Below is the information published by Reuters about what the sinking of Moskva means for Russia's combat readiness.
What capabilities was denied Russia by sinking the Moskva?
Russia has powerful air defense systems deployed in Crimea, which it annexed from Ukraine in 2014, but Moskva was able to provide long-range mobile air protection for the entire Black Sea Fleet, and was a floating command and control center.
Moskva's loss could leave the Russian fleet there more exposed, especially with regard to missions further west of Crimea.
What happened to the crew?
On board Moskva was a crew of about 500 sailors, Russia says it has successfully evacuated all of them to other ships before they return to their home port of Sevastopol in Crimea on Friday.
For its part, Ukraine hinted, on the other hand, that the incident likely led to deaths, but Russia has not mentioned anything about the matter yet.
Will the loss of Moskva change the course of the Ukrainian conflict?
It likely won't change the course of the conflict, but the British Ministry of Defense said its loss would likely prompt Russia to review its position in the Black Sea.
Although the matter is a major blow to the morale of the Russian army, the Russian Navy has not yet played a major role in the war on Ukraine.
Was the ship a role in the conflict?
It is not clear, but some analysts say it might have helped support a possible Russian amphibious landing in the Ukrainian port of Odessa, which has not yet happened due to resistance from Ukrainian forces.
Can Russia easily compensate for Moskva's capabilities?
no.
Although Russia has two other ships of the same class, the Marshal Ustinov and the Varyag, they serve with the Russian Northern Fleet and the Pacific Fleet, respectively.
Was Moskva equipped with unique weapons?
No, it was equipped with anti-ship and surface-to-air missiles, but it was not equipped with the latest generation of Kalibr cruise missiles or 5-times hypersonic missiles.
How big was the shipwreck of the Russian military pride?
It is a bitter loss for the Russian army because the ship, though old, was a symbol of the Black Sea Fleet stationed in Crimea and of Russian military pride.
Western diplomats and experts expect senior officers in the Black Sea Fleet to lose their jobs due to the sinking of the ship.