The naval cruiser was off the coast of the strategic port city of Odessa on the Black Sea when it was struck.
While Ukraine has said they are responsible for the attack, these reports are unconfirmed.
Washington Post foreign correspondent Isabelle Khurshudyan posted on Twitter: “Ukrainian officials claiming they have hit the Russian Naval cruiser, Moskva.
“The warship in the Black Sea was famously told to go f**k itself by the Ukrainian border guards in Snake Island.”
Journalist Mary Ilyushina also tweeted: “BREAKING: Russian Defence Ministry confirms significant damage to cruiser Moskva.
“Ukrainian officials previously said it was hit. Russia says ‘there was a fire’ which set off its munitions and ‘reasons behind it are being established’.”
The Russian Defence Ministry announced: “As a result of a fire, ammunition detonated on the Moskva missile cruiser. The ship was seriously damaged. The crew was completely evacuated.”
The Ministry stated the cause of the fire, however, is under investigation.
Officials in Ukraine claimed on Wednesday that the Moskva was hit twice by a Neptune anti-ship battery, reported Forbes.
The 612-foot long ship was then set alight, with the fire reportedly causing the munitions on board to detonate, reports stated.
Anton Gerashchenko, an advisor to the Ministry of Internal Affairs in Kyiv, announced news of the strike on Telegram.
READ MORE: China’s oil giant set to leave UK and US ‘amid fears of sanctions’
Ukrainian Presidential Advisor Oleksiy Arestovych said in a YouTube broadcast: “A surprise happened with the flagship of the Russian Black Sea Fleet.
“It burns strongly. Right now. And with this stormy sea it is unknown whether they will be able to receive help.
“There are 510 crew members. We don’t understand what happened.”
Russian news agencies have said the Moskva was armed with 16 anti-ship “Vulkan” cruise missiles, with a range of at least 700 km.
The Interfax news agency said the crew of the Moskva had all been evacuated and the cause of the fire was being investigated.