Early on Sunday a massive oil depot fire was raging near Russia's Black Sea resort of Sochi - blamed by the Russian authorities on a Ukrainian drone attack. Sochi's airport in the same area - Adler district - suspended flights.

Ryazan oil refinery, operated by the Rosneft oil company, has halted around half its refining capacity since August 2 following a Ukrainian drone attack last week, three industry sources said.

Russian officials say a Ukrainian drone attack on an oil depot near Russia's Black Sea resort of Sochi has sparked a major fire. Ukrainian President Volodomyr Zelensky announces a prisoner exchange.