Moscow (AFP) – A Ukrainian drone attack sparked a fire at an oil depot in Sochi, the Russian resort that hosted the 2014 Winter Olympic which is 400 kilometres (250 miles) from the Ukrainian border, authorities said Sunday.

Ukraine has regularly hit Russian oil and gas infrastructure in response to attacks on its own territory since Russia began its offensive in February 2022.

"Sochi suffered a drone attack by the Kyiv regime last night," the governor of Russia's Krasnodar region, Veniamin Kondratiev, said on Telegram.

He said drone wreckage hit an "oil tank, which caused a fire" during the nighttime attack.

Sochi's mayor, Andrei Proshunin, said there were no victims and that the fire was put out several hours later.

Images, broadcast by Russian media but whose authenticity AFP could not verify, showed flames and thick plumes of black smoke rising from the site.

Air traffic was briefly suspended at Sochi airport, Russia's air transport regulator Rosaviatsia said.

Ukrainian authorities have not commented on the fire.

Air strikes on Sochi are relatively rare compared to some other Russian cities.

However, Ukrainian drone attacks killed two people there late last month, according to local authorities.

Ukrainian President Volodymyr Zelensky said Sunday that the two sides were preparing a prisoner exchange that would see 1,200 Ukrainian troops return home, following talks with Russia in Istanbul in July.

Kyiv has said it will intensify its air strikes against Russia in response to an increase in Russian attacks on its territory in recent weeks, which have killed dozens of civilians.

The Russian defence ministry said meanwhile that three Ukrainian drones had been intercepted in the Leningrad region, which includes the Baltic port of Saint Petersburg.

Overnight strikes by Russia inside Ukraine also left several people injured, authorities said.

One missile wounded seven people in a residential district of Mykolaiv, a city near the Black Sea in southern Ukraine, Prime Minister Yulia Svyrydenko said.

Three other people were injured in the northeastern Kharkiv region, she added, while authorities also reported injuries in the Zaporizhzhia and Kherson regions in the south.

"The Russians continue to wage war not against Ukrainian forces, but against Ukrainian civilians," Svyrydenko said.

Last week, US President Donald Trump gave his Russian counterpart Vladimir Putin a 10-day ultimatum, until next Friday, to end the conflict in Ukraine.

The air strikes and fighting have not abated, however, and the Kremlin has rejected the idea of a lasting ceasefire in Ukraine, which it sees as a gift to Kyiv's troops.