The incident on the Moskva missile cruiser occurred after ammunition on board exploded, Interfax news agency quoted the Russian Defense Ministry as saying.
“Following a fire on the missile cruiser Moskva, ammunition exploded,” he said in a statement.
Maksym Marchenko, governor of the region around the Black Sea port of Odessa, said in an online post that the 12,500-ton ship was hit by two missiles, without providing evidence.
“The Neptune missiles guarding the Black Sea have caused very serious damage,” he said in an online post.
Reuters was unable to independently verify the two accounts.
Ukraine warned late Wednesday that Russia was stepping up its efforts in the south and east of the country as it seeks full control of Mariupol, in what would be the first major city to fall.
Western governments are sending more military aid to support kyiv.
The Russian Ministry of Defense said Wednesday that 1,026 soldiers from the 36th Ukrainian Marine Brigade, including 162 officers, had surrendered Mariupol, besieged for weeks, and that the port was entirely under its control.
Capturing the industrial district of Azovstal, where the marines are holed up, would give the Russians full control of Ukraine’s main port in the Sea of Azov, strengthen a land corridor to the south, and expand its occupation of the country’s east.
The Ukrainian General Staff said Russian forces were attacking Azovstal and the port, but a defense ministry spokesman said he had no information of any surrender.
“Russian forces are stepping up their activities on the southern and eastern fronts, trying to avenge their defeats,” President Volodymyr Zelenskiy said in a video speech broadcast Wednesday evening.
Reuters journalists accompanying Russian-backed separatists saw flames billowing from the Azovstal area on Tuesday, a day after Ukraine’s 36th Marine Brigade said its troops had run out of ammunition.
The United States on Wednesday announced additional military aid of $800 million, including artillery systems, armored personnel carriers and helicopters. This brings total US military assistance to over $2.5 billion. France and Germany have also promised more.
Senior US officials are weighing whether to send a cabinet member, such as Secretary of State Antony Blinken and Secretary of Defense Austin Lloyd, to kyiv as a show of solidarity, a source familiar with the situation said.
Russia will consider US and NATO vehicles carrying weapons on Ukrainian territory as legitimate military targets, Deputy Foreign Minister Sergei Ryabkov told the TASS news agency.
It will impose tit-for-state sanctions on 398 members of the US House of Representatives and 87 Canadian senators, Interfax quoted the foreign minister as saying, after Washington targeted 328 members of Russia’s lower house of parliament.
Britain has announced new financial measures against separatists.
FREE US FROM WHAT?
Ukraine claims tens of thousands of people were killed in Mariupol and accuses Russia of blocking aid convoys to civilians stranded there.
Its mayor, Vadym Boichenko, said Russia had brought in mobile cremation ovens “to get rid of evidence of war crimes” – a claim that could not be verified.
Moscow blamed Ukraine for civilian deaths and accused Kyiv of disparaging Russian armed forces.
In the village of Lubianka, northwest of kyiv, from where Russian forces had unsuccessfully attempted to subjugate the capital before being driven out, a message to the Ukrainians was written on the wall of a house that had been occupied by Russian troops.
“We didn’t want this…forgive us,” the message read.
The Kremlin says it has launched a “special military operation” to demilitarize and “liberate” Ukraine, a message villagers say was repeated to them by Russian troops.
“To free us from what? We are peaceful… We are Ukrainians,” said Viktor Shaposhnikov, a resident of Lubianka.
Polish President Andrzej Duda said during a visit to Kyiv with his Lithuanian, Latvian and Estonian counterparts that those who committed and ordered crimes must be brought to justice.
The German president did not join them as he had planned.
Mr. Zelenskiy said that there had been no official approach and one of his aides denied a press report that he had rejected the visit because of Mr. Steinmeier’s recent good relations with Moscow.
BIDEN’S COMMENTS ON THE GNOCIDE
The Kremlin has denounced President Joe Biden’s description of Moscow’s actions in Ukraine as amounting to genocide, with spokesman Dmitry Peskov saying it was unacceptable from the leader of a country he says committed crimes.
A first report by an expert mission set up by the Organization for Security and Cooperation in Europe mentions a “catalogue of inhumanity” on the part of Russian troops in Ukraine, according to the American ambassador to the OSCE.
“This includes evidence of direct targeting of civilians, attacks on medical facilities, rapes, executions, looting and forced deportations of civilians to Russia,” said Michael Carpenter.
Russia denied targeting civilians and said Ukrainian and Western war crimes allegations were fabricated.
The kyiv district police chief said 720 bodies had been found in the area around the capital from where Russian forces had withdrawn, and more than 200 people were missing.
The mayor of the northeastern city of Kharkiv, Ukraine’s second-largest city, said shelling had increased dramatically on Wednesday and satellite photos from Maxar Technologies showed long columns of armored vehicles in the region.
Ukrainian forces shot down two Russian planes that were attacking towns in the region, regional governor Oleh Synehubov said earlier.
Reuters could not immediately verify his statement but filmed people in Kharkiv calmly carrying bodies from an apartment building hit by shelling.