"This does not mean that they are drowned, just incapacitated, meaning they can't carry out any offensive actions," Yigal Levin, a military expert and former officer of the Israel Defense Forces, told Radio NV.
An underwater drone attack in Sevastopol reportedly damaged a Russian minesweeper and a dam on Oct. 29. Russia accused Ukraine of sending nine drones to the port city. Ukraine hasn't confirmed its involvement.
Following the attack, Russia launched strikes against critical infrastructure in 10 Ukrainian regions on Oct. 31, causing power and water outages across the country.
Russian President Vladimir Putin then said it was "partly response" to the Sevastopol attack.