Ukraine struck a Russian submarine and warship in an overnight attack against a major Russian naval base in Crimea, a Ukrainian official has said.
If confirmed, it is thought to be the first known strike against a Russian submarine in the war.
Russia said Kyiv had launched cruise missiles that damaged two ships at the Sevastopol shipyard, home to its Black Sea Fleet. It also said there had been a thwarted attack by Ukrainian speedboats.
Unconfirmed images on social media indicated that a Russian diesel submarine had been at the dry dock, which is used to carry out repair work.
Videos showed flames blazing.
Andriy Yusov, a Ukrainian military spy agency official, told the Reuters news agency: “We confirm a large landing vessel and submarine were hit. We do not comment on the means [used] for the strike.”
Russia’s defence ministry said Ukraine had launched 10 missiles and three speedboat attacks on the port.
Seven of the missiles were intercepted and all three boats destroyed, it said in a statement on its Telegram channel.
“As a result of being hit by enemy cruise missiles, two ships under repair were damaged,” the ministry said.
Mikhail Razvozhayev, the Moscow-installed governor of Sevastopol, the largest city in Crimea and a major Black Sea port, said on Telegram that at least 24 people were injured.
“All emergency services are working on the site, there is no danger to civilian objects in the city,” Mr Razvozhayev said.
The strategic shipyard on the peninsula, which Russia annexed from Ukraine in 2014, builds and repairs ships and submarines of the Russian Black Sea Fleet.
The fleet has launched numerous drone and missile attacks on Ukraine.
Mr Razvozhayev posted a night-time photo of flames engulfing what seemed to be port infrastructure. Russian Telegram channels posted videos and more photos of massive flames at a facility alongside the water.
Rob Lee, a military analyst, posted a series of videos and images on social media purporting to show the strike. He cited another social media channel as identifying the submarine that had allegedly been at the dry dock as being the Black Sea Fleet’s Rostov-on-don Project 636.3 diesel submarine.
The landing ship was identified as the Russian Baltic Fleet’s Minsk Project 775 Ropucha-class large landing ship.