Ukraine's attacks on Crimea are having a significant psychological and operational impact on Russian forces, Western officials told journalists, according to the BBC.
In recent weeks, a series of audacious strikes have been carried out on Crimea, including explosions at the Saki airbase, explosions at an ammunition dump, and multiple alleged drone attacks on Sevastopol.
On Saturday, footage circulated on social media appeared to show smoke billowing from a fresh drone attack on Russia's Black Sea fleet headquarters in Sevastopol.
Ukrainian officials have avoided claiming public responsibility for all of the attacks but have often implied responsibility. An unnamed Ukrainian official told The New York Times that an "elite" military unit "behind enemy lines" was responsible for the blasts in Saki.
The attacks could be the work of Ukrainians who have trained closely with US special operators since 2014, Insider's Stavros Atlamazoglou previously reported.
The Western officials, who spoke to the media unattributably on background, said that the strikes had depleted Russia's Black Sea fleet, with more than half of their naval jets now out of action, the BBC reported.
The once revered fleet has also suffered significant losses of its ships at the hands of Ukraine, including the sinking of its Moskva warship in April.
The setbacks have forced the fleet to adopt a defensive posture, officials said.
Russia annexed the Crimean Peninsula from Ukraine in 2014, which most of the international community considered illegal.
Up until August, Crimea has been considered out of reach of Ukrainian attacks, officials said, per the BBC.
The attacks on the Saki air base on August 9, which destroyed eight fighter jets, caused Russian tourists to flee from the peninsula and psychologically affected Moscow, officials told the BBC.
Crimea has provided the main supply route for Russian invasion forces in southern Ukraine, and the recent attacks have weakened this.
Russian President Vladimir Putin is reported to have replaced the commander of the Black Sea Fleet following the explosions, demoting admiral Igor Osipov in favor of his former deputy, Viktor Sokolov, state news agency RIA said, according to Reuters.
If confirmed, Osipov's demotion would mark the most major sacking of a military official since Russia began its invasion of Ukraine in February.
According to the BBC, Russian state media reported that Sokolov told officers they would receive 12 new vessels, indicating that Moscow is attempting to re-arm its weakened fleet.
Following the recent attacks, Ukrainian President Volodymyr Zelensky said the war must end with Crimea's liberation.
"Crimea is Ukrainian, and we will never give it up," the president said, according to the BBC, without directly mentioning the blasts.