KYIV — Ukraine has hammered Russia’s Black Sea fleet so hard that Moscow is shifting much of it away from Crimea, allowing Kyiv to reopen its ports to grain vessels despite Russia’s blockade threats.

“As of today, Russia is dispersing its fleet, fearing more attacks on its ships. Some units are relocating to the port of Novorossiysk. They try not to visit Sevastopol so often because they don’t feel safe there anymore,” Ukrainian navy spokesperson Dmytro Pletenchuk told POLITICO.

Ukraine unleashed a series of carefully planned attacks against the fleet and parts of its crucial infrastructure in recent weeks — destroying key air defense systems, landing commandos on Crimea, and pounding the fleet’s base in Sevastopol in an attack that heavily damaged a submarine and a missile carrier and put the fleet’s dry dock out of commission.

The coup de grâce was a missile attack on the fleet’s headquarters in downtown Sevastopol.

Ukrainian forces also control drilling rigs in the Black Sea as well as Zmiiniy Island — the famous island where Ukrainian forces said: “Russian warship, go fuck yourself” in the early days of the war.

That’s made naval operations in the western part of the Black Sea perilous for Russia, allowing grain ships to dock at Ukrainian ports with much less fear of being stopped and boarded by the Russians.

“Now ships and boats of the Black Sea fleet of the Russian Federation do not actually sail in the direction of the territorial sea of Ukraine. From time to time, they appear on the coast of Crimea, but not closer. They do not dare to go beyond the Tarkhankut Peninsula,” Natalia Humeniuk of Ukraine’s Army Operational Command South, told Ukrainian television on Wednesday, referring to the point that marks the westernmost extremity of Crimea into the Black Sea.

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She said Russian warships had been pushed back at least 100 nautical miles from the coast controlled by Ukraine.

That’s allowed Kyiv to restart grain exports from three Black Sea ports — reopening a route that the Kremlin had tried to throttle after pulling out of the U.N.-negotiated grain deal in July.

An official with the Ukrainian Armed Forces Command South, who was granted anonymity due to the sensitivity of the issue, said the Ukrainian military counted at least 10 Russian Black Sea fleet vessels that used to be based in Crimea and have now shifted east to the Russian port of Novorossiysk.

“They stopped being there all the time,” Pletenchuk said.

While cargo ships are again sailing to Ukrainian ports, Humeniuk warned that the threat isn’t over.

Although Russian warships have made themselves scarce, Russian planes are still flying over the sea. Russian forces frequently bomb Zmiiniy Island and attack cities and towns on the Black Sea coast of Ukraine with drones.

There is also the danger that Russia may lay mines to block sea routes, British intelligence said on Wednesday.

But for the moment, the situation on the Black Sea is a huge embarrassment for the Kremlin, as its second-largest naval force has been humbled by a country with almost no navy.

The Black Sea fleet has been a bone contention between Ukraine and Russia since the collapse of the Soviet Union. Moscow had a special arrangement with Kyiv to keep basing the fleet in Sevastopol, and concern over those basing rights was one of the reasons Russian President Vladimir Putin gave for his illegal annexation of Crimea in 2014.

The challenge to the fleet also endangers Russia’s hold on Crimea, said Volodymyr Zablotskiy, a Ukrainian military and naval expert.

“Without Crimea, this expansion fleet will not be viable, and the capabilities of the Kremlin and the region will be limited. These are the strategic consequences of our future de-occupation of the peninsula,” he said. “It is the fleet that enables the logistics of the Russian forces in this direction. And the key to it is the possession of Sevastopol.”