A single Ukrainian kamikaze naval drone destroyed or damaged four Russian patrol boats in an operation last month, Kyiv's military intelligence (HUR) said on June 20.
Speaking on national television, HUR spokesperson Andrii Yusov said even though Moscow's forces had defenses in place to protect against such attacks, the agency's Magura V5 drones are still able to get around them.
"We've seen in the last few operations where the enemy has planned everything out and did it right, the Magura breaks through these sea fortifications and fire barriers, and then the next drone goes straight to the target.
"As we saw when four Tuna speed boats were hit at once, aviation, artillery, small arms – none of it worked.
"And, in fact, one Magura drone destroyed, damaged, and hit four enemy speedboats. And this is a very good result."
Information on Russian casualties is still being clarified, Yusov told the Kyiv Independent.
The military intelligence agency initially reported only two boats had been hit during the attack in Vuzka Bay on May 30, which lies at the Chornomorske town on Crimea's western coast.
In order to thwart the attack, Russian forces scrambled their aircraft 32 times, including Su-27/30/35 and MiG-29 jets, Be-12 and An-26 aircraft, and Ka-27/29 and Mi-8 helicopters, HUR said.
The Magura V5 is a multi-purpose naval drone developed by Ukraine and has been extensively used in attacks against the Russian Black Sea fleet, mainly by ramming into enemy vessels while loaded with explosives.
Ukraine previously destroyed several Russian ships with Magura drones, including a landing ship Caesar Kunikov, a Sergei Kotov patrol ship, high-speed Serna and Akula landing crafts, and a Tarantul-class Ivanovets missile corvette.
Newer versions of the Magura V5 are equipped with air-to-air guided missiles.