Ukrainian special forces carried out a raid on a Russian air base in Crimea more than 200 kilometers behind front lines, according to the country’s military.
Ukraine’s air force says nine Russian warplanes were destroyed in the blasts, a claim Moscow has denied.
One person was reported killed in the series of explosions at a Russian military air base near the seaside resorts of the annexed Crimean peninsula on Tuesday.
There has been speculation as to what caused the explosions, as the rockets supplied with US-donated HIMARS launch systems are believed to have a range of about 85 km.
Russia claimed the munition had detonated, but a senior Ukrainian official told Sky News that Ukrainian Special Forces carried out the operation.
Meanwhile, 13 people have been killed following a Russian bombing attack in Ukraine’s central Dnipropetrovsk region, the area’s governor said.
Valentyn Reznychenko said Russia “directed 80 rockets at residential areas” while “people were sleeping in their homes”.
People fled the Crimean beach as flames rose into the sky
Witnesses said they heard at least 12 explosions at around 3.20pm local time (1.20pm BST) from the Saky base in Crimea.
Videos posted on social media showed people fleeing a beach as flames and plumes of smoke rose from several locations.
Witnesses also reported a fire on a runway and damage to nearby houses, Crimea Today News said on Telegram.
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Image: Explosions were heard for over an hour in the area of Novofedorivka military airport, Saki region of occupied Crimea
Crimea’s health department said one civilian had been killed, while another person had been treated in hospital for moderate injuries and five others suffered minor injuries.
Russia annexed Crimea from Ukraine in 2014 and used it as a launch pad for its neighbor’s invasion in February.
Russian warplanes have used the base to attack areas of southern Ukraine.
Moscow said the explosions were the detonation of stored ammunition and had not been caused by an attack.
Russia’s main news agencies quoted an unnamed ministry source as saying that “only a violation of fire safety requirements is considered the main reason for the explosion of several ammunition stores at the Saky airfield.”
The source added: “There are no signs, evidence or, much less, facts (indicating) a deliberate impact on ammunition stores.”
There were suggestions on Ukrainian social media, however, that the base had been hit by long-range missiles fired from Ukraine.
President Zelenskyy, speaking on Telegram, vowed that that war with Russia “started with Crimea and must end with Crimea, with its liberation.”
He added: “Russia has turned our peninsula, which has always been and will always be one of the best places in Europe, into one of the most dangerous places in Europe.
“But we will return to Ukrainian Crimea.”
In an apparently sarcastic post on Facebook, the Ukrainian Ministry of Defense said: “The Ministry of Defense of Ukraine cannot establish the cause of the fire, but once again reminds of fire safety rules and the ban on smoking in unspecified locations.”
It added: “We cannot rule out that the occupants ‘accidentally’ found some characteristic ‘badge’, ‘business card’ or even ‘DNA’.”
Since the war began, Russia has reported numerous fires and explosions at ammunition storage sites on its territory near the border with Ukraine, blaming some of them on Ukrainian attacks.
Ukraine has not commented.
Also on Wednesday, the UK Ministry of Defense said in its latest intelligence report that Russian commanders likely continue to face the competing priorities of bolstering Moscow’s Donbas offensive and strengthening defenses against Ukraine’s anticipated counter-attacks in the south.