Rail deliveries to Russia's Black Sea port of Taman will be restricted until further notice, Russian Railways said on its website, after Russian officials said a fuel depot had caught fire near a crucial bridge linking mainland Russia to Crimea.
The company did not provide the reason for the restrictions.
Last week, Moscow accused Ukraine of setting fire to an oil depot in Sevastopol in Crimea.
Flames and black smoke billowed over large tanks emblazoned with red lettering reading "Flammable" in videos from Taman posted on Russian social media, though Reuters could not independently verify either the fire reports or the videos.
Taman's oil transhipment hub, which lies across the Kerch Strait from Crimea, at the mouth of the Azov Sea and Black Sea, has the capacity to handle 20 million tonnes of crude oil, oil products and liquefied petroleum gas a year.
In 2022, it handled 7.3 million tonnes of oil products from Russia, Kazakhstan and Kyrgyzstan.
The Russian-built Crimean Bridge carrying road and rail traffic across the Kerch Strait was damaged last October in an attack that Russia blamed on Ukraine, and has yet to be fully restored.
(Reporting by Reuters; Editing by Mark Trevelyan and Kevin Liffey)