Ukraine's defense ministry says it carried out a drone attack that damaged a Russian naval ship off the southern coast of Russian-occupied Crimea.

The defense intelligence agency said on social media on Tuesday that maritime drones attacked Russia's Black Sea Fleet patrol ship Sergey Kotov near the Kerch Strait from Monday night through Tuesday. The strait lies between southern Russia and the Crimean Peninsula.

The chief of the Ukrainian presidential office Andriy Yermak wrote on social media that Russia's Black Sea Fleet is "a symbol of occupation," and that "it cannot be in the Ukrainian Crimea."

The Ukrainian military said last month their forces destroyed a large Russian landing ship off Crimea.

They vow to continue attacks on the Russian navy operating in the surrounding waters.

The Ukrainian defense intelligence agency also commented on an explosion that damaged a railway bridge in Russia's central Samara region on Monday.

The agency did not mention any link to the blast, but pointed out that the railway line was used to "transport military cargo, in particular, engineered ammunition" produced by a plant in the region.

Ukraine is also stepping up attacks on Russian infrastructure, including military facilities.

Russia's state-run Tass news agency on Tuesday reported an explosion at an oil reservoir in the country's western region of Belgorod, near the Ukrainian border.