KYIV, Ukraine — Ukraine President Volodymyr Zelenskyy claimed on Tuesday that recent Ukrainian attacks have denied the Russian fleet safe bases and secure maritime corridors in the western part of the Black Sea, as Kyiv’s troops look to squeeze the Kremlin’s occupying forces out of the Crimean Peninsula.

Crimea provides rear support for Moscow’s battlefield efforts further west and has been a frequent target for Ukrainian forces during the war since Russia’s invasion of Ukraine.

“The Russian fleet is no longer capable of operating in the western part of the Black Sea and is gradually retreating from Crimea,” Zelenskyy claimed, without providing evidence. “This is a historic achievement.”

Ukraine is keen to show that billions of dollars’ worth of weapons supplied by its Western allies have allowed it to make progress in the fighting, as the conflict enters its 21st month amid a broad stalemate.

With the war poised to extend into another winter and likely deep into next year, Kyiv is pushing its allies to provide it with more military assets. Ukrainian officials, meanwhile, are competing for the world’s attention with the Israel-Hamas war.

Ukraine’s forces are not yet able to strike at any target in Crimea and its waters but that capability is coming closer, Zelenskyy told a meeting of the Crimea Platform, a diplomatic forum, in Prague via video link. He did not elaborate.

The Russian Defense Ministry said its forces hit three Ukrainian sea drones in the Black Sea early Tuesday.

Russia annexed Crimea, in eastern Ukraine, in 2014. In February last year, it launched a full-scale invasion that also aims to annex the Ukrainian provinces of Donetsk, Kherson, Luhansk, and Zaporizhzhia.

Since the collapse last August of a deal allowing Ukraine to safely export grain despite the war, Zelenskyy said, a new Black Sea export corridor has allowed some 50 ships to set sail, with more than 50 more departures expected. He did not provide details.

In other developments:

1. German defense conglomerate Rheinmetall and Ukrainian Defense Industry have formed a joint venture, Ukraine Prime Minister Denys Shmyhal announced during the German-Ukrainian Business Forum in Berlin. He called it “a significant event that elevates cooperation between our countries to a qualitatively new level.” The joint company will provide maintenance and repair services for the equipment supplied to Ukraine by its partners.

2. Ukraine’s air force said it shot down six Russian drones over the central and southern regions of the country on Monday night. Russia launched the drones from Crimea, the Ukrainian army said. Russian shelling killed two Ukrainian civilians in the south of the country and injured at least 20 other in the southeast, the presidential office reported.