Ukrainian drones have set oil tanks on fire at an depot in Russia's southern Rostov region, Russian Telegram channels reported on Wednesday.
Russia's air defence units destroyed four drones over the Rostov region overnight, the Russian defence ministry and Rostov's governor, Vasily Golubev, said on the Telegram messaging app, but made no mention of an attack on an oil depot.
The Baza Telegram channel, which is close to Russia's security services, said that three tanks were burning at an oil depot in the Kamensky district of the Rostov region after two drones fell on the area.
Videos posted on Russian social media showed what looked like large tanks ablaze at night. Reuters was able to identify the location of one of the videos as in Rostov's Kamensky district.
There was no immediate comment from Ukraine.
A fuel storage depot in the Kamensky district was attacked in early August as well.
The attack comes while tanks were still on fire at another Rostov's oil depot, in the Proletarsk district, some 10 days after a Ukrainian attack, Russian Telegram channels report.
Separately, Alexander Gusev, the governor of the Voronezh region that borders Ukraine, said debris from a Ukraine-launched drone over the region sparked a fire "near explosive objects."
The fire had been extinguished, Gusev said on Telegram.
The Russian defence ministry said eight attack drones were destroyed over the Voronezh region, but it provided no further detail.
Earlier Ukraine's Volodymyr Zelenskiy said the war with Russia will eventually end in dialogue, but that Kyiv has to be in a strong position and that he will present a plan to US President Joe Biden and his two potential successors.
The Ukrainian leader said Kyiv's three-week-old incursion into Russia's Kursk region was part of that plan, but that it also comprised other steps on the economic and diplomatic fronts.
"The main point of this plan is to force Russia to end the war. And I want that very much - (that it would be) fair for Ukraine," he told reporters in Kyiv of the war launched by Russia's full-scale invasion in February 2022.
Overnight Russian missile and drone attacks across Ukraine killed at least five people, a day after Moscow's biggest air attack of the war on its neighbour.
Two people were killed when a hotel was "wiped out" by one of several missiles in the central city of Kryvyi Rih, regional officials said. Three died as the country was also hit with scores of drone attacks.
Several Russian military bloggers said Moscow's attacks were an "act of retaliation" for Ukraine's surprise incursion into Russia's western Kursk region - the first such action since World War II.
But Zelenskiy said it would be for Ukraine to retaliate, once again calling for help from the West.
Zelenskiy said he hoped to go to the United States in September to attend the UN General Assembly in New York and that he was preparing to meet US President Joe Biden.
His remarks indicated that he sees the main potential forum for talks as a follow-up international summit on peace, at which Ukraine has said it wants Russia to have representatives.
Russian President Vladimir Putin has said any peace deal needs to start with Ukraine's acceptance of "realities on the ground", that would leave Russia with possession of substantial chunks of four Ukrainian regions as well as Crimea. Now Ukraine says it controls more than 1200 sq km of Russia's Kursk region.
"There can be no compromises with Putin, dialogue today is in principle empty and meaningless because he does not want to end the war diplomatically," Zelenskiy said at the news conference.
He said the offensive into the Kursk region had reduced the number of governments around the world calling for Ukraine to make compromises with Russia to end the war and give up swathes of territory.
