The Russian Ministry of Defence initially said one service member was killed on Friday but then issued a statement saying he was missing following the attack in the port city of Sevastopol.

The Crimean Peninsula, which Russia annexed from Ukraine in 2014 in a move largely considered illegal, has been a frequent target since Russian President Vladimir Putin ordered a full-scale invasion of Ukraine almost 19 months ago.

The Russian-installed governor of Sevastopol, Mikhail Razvozhayev, said no one was injured outside of the burning headquarters building.

The Ukrainian military claimed responsibility for the attack.

“We promised that ‘there will be more,’” Lieutenant General Mykola Oleschuk, the air force commander, said in a social media post that thanked pilots and showed video of air sirens blazing and smoke rising from the building.

Razvozhayev said on social media earlier Friday that missile fragments had fallen near a theatre and urged residents to stay clear of the site.

“The headquarters of the fleet have been hit in an enemy missile attack,” Razvozhayev said.

In a second post, he warned that another aerial attack could be imminent, urging residents of the city, which is home to more than 500,000 people, to remain indoors.

“Attention everyone! Another attack is possible. Please do not go to the city centre. Do not leave buildings,” he said.

“Everyone who is near the headquarters of the fleet – at the sound of the siren proceed to shelters,” Razvozhayev added.

He said rescue workers were at the scene, adding, “Firefighters are taking all measures to eliminate the fire as soon as possible.”

Later on Friday, the Moscow-appointed governor of Crimea, Sergei Aksyonov, said on Telegram that several cruise missiles had been intercepted over Crimea.

“Over the territory of the Republic of Crimea, air defence has shot down cruise missiles,” he said, without specifying how many missiles were shot down.

Ukrainian and Russian attacks in and around the Black Sea have increased since Moscow withdrew from an accord that allowed safe passage to civilian cargo ships from three Ukrainian ports.

Ukraine has urged its allies to provide its armed forces with long-range missiles so it can target positions deeper inside Russia-controlled territory.

Western leaders have hesitated over concerns Ukraine could target Russian territory and thereby escalate the conflict.

Both France and the United Kingdom, however, have supplied Kyiv’s forces with the weapons.

As part of the increasingly frequent barrages on Crimea, Ukraine said earlier this week it had attacked a military airfield near the town of Saky.

A source in Ukraine’s SBU security service said there were at least a dozen warplanes and Pantsir missile defence systems at the airfield when the attack took place.

The airfield also housed a training centre for operators of drones that Russia has used to target Ukraine.

The SBU source said that Ukraine had deployed a swarm of unmanned aerial vehicles that “overwhelmed Russian air defences” and then launched Neptune cruise missiles.

Crimea bridge

Kyiv has also repeatedly targeted and hit – the only bridge that connects the peninsula to the Russian mainland, on several occasions leaving damage that took weeks to repair.

The last significant attack in July affected the road section of the bridge, which can also accommodate rail traffic and has also been used to transport military equipment.

Russian officials said on Friday that traffic across the bridge had been temporarily paused.

Civilian maritime traffic was stopped earlier on Friday in Sevastopol, Russian-installed authorities said, without providing details.

The Russian Defence Ministry said its forces had shot down one guided missile and two drones that had targeted the peninsula.