Russia's navy is using trained dolphins to step up security at its Sevastopol Black Sea fleet base, according to UK intelligence.
The mammals are intended to "detect and counter" enemy divers, British intelligence reported.
Ukraine counteroffensive continues
The move comes as Ukraine launches its counteroffensive to return all occupied lands to Kyiv’s control. It already has targeted infrastructure near Crimea. Russia believes the Black Sea base could be a key target for attacks from Ukraine.
In addition to deploying dolphins, Russia’s new defenses near the Black Sea harbor include multiple layers of nets and booms across the entrance of the base.
President Volodymyr Zelensky said battlefield progress in Ukraine's counteroffensive against Russian forces had been "slower than desired," the BBC reported on Wednesday.
"Some people believe this is a Hollywood movie and expect results now. It's not," it quoted Zelensky as saying in an interview.
Russian history of spy marine animals
Last month, the Norwegian Directorate of Fisheries advised beachgoers to "avoid contact" with a well-known beluga whale that's suspected of being used for Russian espionage.
The warning came in response to the whale's travels to a densely populated area, putting him at far greater risk of injury or death. The whale, nicknamed Hvaldimir, became famous in 2019 after it was spotted wearing a specially made harness with mounts for a camera, leading to the "Russian spy" allegations.
Reuters contributed to this report.