A fuel depot caught fire overnight in the Russian village of Volna, close to the bridge to the Crimean peninsula, the local governor said early Wednesday.
"A tank with petroleum products caught fire in Volna village of Temryuksky district. The fire has been assigned the highest level of severity," Krasnodar Krai governor Veniamin Kondratyev said on Telegram, without mentioning the cause of the blaze.
"According to preliminary information, there are no dead or injured," he said, adding there was no threat to residents.
"Everything possible is being done so that the fire does not spread further."
Volna is at the end of the bridge over the Kerch Strait linking Russia to Crimea, which Moscow annexed from Ukraine in 2014.
In October 2022, the Russian-built bridge was partially destroyed by a truck bomb in an attack Moscow blamed on Ukraine, although Kyiv has denied it.
The bridge serves as a vital link for transporting supplies to Russian soldiers in Ukraine.
Russia and Crimea have been the target of a series of attacks in recent days ahead of an expected counteroffensive by Ukrainian forces, although Kyiv has also not claimed responsibility for the incidents.
A suspected drone attack hit an oil depot in the Crimean port city of Sevastopol on Saturday while explosive devices derailed two Russian freight trains near the border with Ukraine on Monday and Tuesday.
In southern Ukraine's Kherson region, four people were killed and seven injured in Russian strikes, the regional administration said Wednesday.
A 66-year-old man was killed overnight by Russian shelling in the village of Kozatske.
Air raid alerts were sounded in several cities across Ukraine early Wednesday.
Kyiv was targeted in a drone attack but there were no casualties, the city's military administration said.
"According to preliminary information, all enemy targets were identified and shot down in the airspace around the capital," it said.
Ukraine over the winter strengthened its air defences, including with US Patriot systems after it appealed to Western allies to help fend off Russian attacks on the energy grid.
Ukraine says it has been preparing for months a counteroffensive aimed at repelling Russian forces from the territory they currently hold in the east and south.