Ukrainian forces have reportedly carried out their largest-ever drone attack in Crimea which Russia has unilaterally annexed.

This comes as the Ukrainians conduct counteroffensive operations in the southern Zaporizhzhia region.

Russia's defense ministry said on Friday that Ukraine attacked Crimea with 42 drones, all of which were shot down by Russian forces.

Ukraine's military intelligence agency confirmed to local media that its forces had carried out a drone attack on a Russian military base.

A US think tank, the Institute for the Study of War, quoted a Kremlin-affiliated military blogger as saying that it was "the largest Ukrainian drone strike in recent months."

Ukraine's military intelligence agency on Thursday released footage which it says was of an operation in which Ukraine's special forces landed on a cape in western Crimea, and hoisted the Ukrainian flag.

Ukraine's defense intelligence chief Kyrylo Budanov told local media that the operation shows that Crimea has not been forgotten.

He said the operation will not end in a single strike, and that the territory's liberation is "not far away."

Ukrainian forces are carrying out a counteroffensive around the village of Robotyne in the southern region of Zaporizhzhia where Russia has built up its defenses.