Russia on Thursday withdrew from Snake Island, a craggy speck of land in the Black Sea, handing Ukraine a symbolically-potent political victory and depriving Moscow of a strategic outpost for its air defenses and electronic warfare systems.

The island's capture by Russian forces on the first day of their invasion entered Ukrainian folklore as a tale of bold resistance after Kyiv said that one of its border guards had told a Russian warship demanding their surrender to "f*** off."

Lifting the spirit of Kyiv residents worn down by Russia's grinding eastern advance, Ukraine's military said on Thursday it had driven Russia from the island with artillery and missile strikes.

Russia cast the exit as a deliberate withdrawal that was an act of goodwill to demonstrate it was not obstructing UN efforts to unblock grain that is stranded at Ukraine's Black Sea ports, an assertion dismissed by Kyiv as untrue.

Military analysts said Russia's presence on the island had become untenable because of Ukrainian attacks on Russian supply lines to the outcrop from Crimea, and that much of the equipment deployed there had already been destroyed.

"Ukrainian aviation and Bayraktar drones effectively cut off supplies to the Russian contingent that was deployed there," Oleksandr Musiyenko, a Kyiv-based military analyst, said.

Ukrainian armed forces commander Valeriy Zaluzhnyi said Ukrainian-made Bohdana howitzers played an important role in driving out the Russian forces and thanked foreign partners for their support.

"Trying to retain positions on a small and barren piece of land in range of heavy artillery and without the means to suppress that artillery is a recipe to steadily accumulate casualties," Jack Watling, a military expert at RUSI in London, said.

Russia had deployed air defenses including TOR and Pantsir systems on the island as well as electronic warfare and radio intelligence units.

"We practically destroyed all the equipment on the island. The garrison's presence had simply become pointless. What could rank and file soldiers with automatic weapons do on the island? Nothing. There isn't even fresh water there," Oleg Zhdanov, a Kyiv-based military analyst, said.

The lost Kremlin foothold gives Ukraine a freer hand to use military drones and operate in the western Black Sea, but it is unlikely to help ease the crisis over Ukraine's blockaded grain, the analysts said.

It was also unlikely that Ukraine would itself take up positions and deploy anti-ship weapons on the island to try to beef up its coastline defenses because the island remained within the firing range of Russian forces, Zhdanov said.

Since Russia invaded on Feb. 24, Ukrainian grain shipments have stalled from its Black Sea ports and millions of tonnes of grain are stuck in silos.

Moscow says the onus is on Kyiv to remove mines from the ports to free up shipping lanes and says Western sanctions against it are worsening the situation.

"This will not unblock the export of grain. Russia retains shooting control over this area of the waters. One option is that the United Nations forms a humanitarian convoy, then maybe there would be a chance to get these ships out with grain from our ports for export," Zhdanov said.

He said that Western supplies of arms including Harpoon anti-ship weapons meant that Russian warships had not come in to support their forces on the island.