The strike came as Ukraine prepares for a long-promised counter offensive to push Russian forces back from territory they seized since invading in February 2022.

Ukraine says control of all its legal territory, including Crimea, is a key condition for any peace deal. Russian forces occupied the peninsula in 2014.

Moscow has accused Kyiv of sending waves of aerial and seaborne drones to attack Crimea.

Sevastopol governor Mikhail Razvozhaev said only one drone hit the oil tanks.

“The enemy … wanted to take Sevastopol by surprise, as usual, by staging a sneak attack in the morning,” Razvozhaev wrote on the Telegram app. Russian firefighters had shown how to defeat a major blaze “and prevent a catastrophe”, he added.

02:03

China to send envoy to Ukraine after Xi and Zelensky hold first call since Russian invasion

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Ukraine lacks longer-range missiles that can reach targets in places such as Sevastopol, but has been developing drones to overcome this hurdle.

Ukrainian officials do not usually claim responsibility for explosions at military sites in Crimea, although they sometimes celebrate them using euphemistic language.

Andriy Yusov, a Ukrainian military official, did not say Ukraine carried out the attack. Instead, he told RBC the blast was “God’s punishment” for a Russian strike on the Ukrainian city of Uman on Friday that killed 23 people.

“This punishment will be long-lasting. In the near future, it is better for all residents of temporarily occupied Crimea not to be near military facilities and facilities that provide for the aggressor’s army,” RBC quoted Yusov as saying.

Volodymyr Zelensky: Russian soldiers are all responsible for war crimes

Ukrainian President Volodymyr Zelensky said Kyiv would do all it could to ensure that those responsible for the attack on Uman be held accountable as soon as possible.

“You are all terrorists and murderers and you must all be punished,” he said in an evening video address.

Volodymyr Zelensky did not refer directly to the months-long fighting for the eastern Ukrainian city of Bakhmut, focus of repeated Russian assaults that have slowly closed in on the centre.

Wagner threatens Bakhmut withdrawal

The attacks are largely led by the Wagner private army. Its founder, Yevgeny Prigozhin, said his forces had advanced between 100 (300 feet) and 150 metres on Saturday and claimed pro-Kyiv units now only controlled three sq km (1.2 sq miles).

Prigozhin, speaking in a voice message posted to Telegram, repeated his complaints that Moscow was not sending his men enough ammunition. Prigozhin has made over-optimistic statements about Wagner’s military successes in the past and Reuters was not able to immediately verify his latest claim.

The head of the Wagner Group of Russian mercenaries, Yevgeny Prigozhin, has threatened to withdraw his troops from the embattled city of Bakhmut in Ukraine.

“Every day we have stacks of thousands of bodies that we put in coffins and send home,” Prigozhin said in an interview with Russian military blogger Semyon Pegov published on Saturday.

Losses were five times higher than necessary because of the lack of artillery ammunition, Prigozhin said.

The Wagner chief said he has written to Russian Defence Minister Sergei Shoigu asking for supplies as soon as possible. “If the ammunition deficit is not replenished, we are forced – in order not to run like cowardly rats afterwards – to either withdraw or die,” the 61-year-old asserted.

Prigozhin said he would probably be forced to withdraw some of his troops, but warned that this would mean that the front would collapse elsewhere.

There has been fighting over Bakhmut in eastern Ukraine for months. Casualties are high on both sides. The Ukrainian defenders control only a small area in the west of the city.

Kyiv said that Moscow would fail in its effort to cut off Bakhmut from Ukrainian supply routes.

“The Russians have been talking for several weeks about conquering the ‘road of life’ as well as keeping fire control over it. In reality, everything is different,” a spokesman for the Eastern Group of the Ukrainian Armed Forces, Serhiy Cherevaty, told online outlet zn.ua on Saturday.

Although the connecting road from Bakhmut to Chasiv Yar is being fought over, the Russians are not succeeding in disrupting the logistics of the defenders, Cherevaty said. The information could not be independently verified.

The supply of provisions, weapons and ammunition is secured, Cherevaty explained. The Ukrainian forces were maintaining their positions along the road and engineers had already laid new roads to Bakhmut. “All this allows us to continue holding Bakhmut,” he said.

In its situation report, the Ukrainian general staff also spoke of “unsuccessful attempts” by Russian forces to make gains in the area.

Russia’s Wagner Group could soon cease to exist, founder tells war blogger

Two killed in strike on Russian village: governor

Two people were killed when a Ukrainian missile hit a Russian village near the countries’ border, the regional governor said on Sunday.

Missiles hit the village of Suzemka, to the east of the frontier between the two countries, according to Alexander Bogomaz, the governor of Bryansk oblast.

“As a result of the strike inflicted by Ukrainian nationalists, unfortunately, two civilians were killed,” he said in a message posted on Telegram.

“According to preliminary data, one residential building was completely destroyed, two more houses were partially destroyed.”

It comes after a week in which Russia renewed heavy missile attacks on Ukrainian cities, killing 23 people including a baby boy, and a massive fire broke out in Moscow-annexed Crimea after a suspected drone attack.

Moscow-installed officials in eastern Ukraine also reported that Ukrainian shelling had killed nine people including an eight-year-old girl in the city of Donetsk.

Reporting by dpa, Reuters, Agence France-Presse