A Ukrainian drone strike set ablaze a Russian fuel storage facility in the Crimean port of Sevastopol early on Saturday, sending a vast column of black smoke into the sky in the latest attack on the Russia-occupied peninsula.

The city’s Moscow-installed governor blamed Ukraine and later said the fire had been put out before a disaster occurred.

A Ukrainian military intelligence official said more than 10 tanks of oil products with a capacity of about 40,000 tonnes intended for use by Russia’s Black Sea Fleet were destroyed, RBC Ukraine reported.

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.

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.

Ukrainian President Volodymyr Zelenskiy 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.

Zelenskiy 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.

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.