Ukraine shows off its next-generation 20-foot-long underwater drone designed to sink Russian warships from below the surface

• Ukraine has unveiled a new 20-foot-long underwater drone to attack Russian warships.
• Until now, Ukraine has been attacking Russia's Black Sea Fleet mainly using surface naval drones.

Ukraine has unveiled a 20-foot-long underwater drone to attack Russian warships from under the sea, reports say.

The vessel, named Marichka, could give Ukraine a new dimension to its attacks on Putin's Black Sea fleet, as until now, attacks have been mainly carried out by surface naval drones.

"Marichka will hit the ships on the underwater part, which can be even more destructive for the warships," the specialist naval-defense news website Navalnews said.

"A swarm of these suicide underwater uncrewed vehicles is very hard to defend," it said.

Ukraine previously unveiled a much smaller submarine drone called the Toloka. But The Telegraph reported that it was still being determined whether it had been used to attack Russian ships.

The Marichka has a range of about 600 miles and can perform attack, transport, or reconnaissance missions, Navalnews reported.

A newly released video appears to show the Marichka being lowered into the sea to be tested, and another video animation shows the specifications of the drone.

The payload capacity of the drone is yet to be revealed.

The Marichka has been developed by volunteer engineers, known as Ammo Ukraine, and it is estimated to cost 16 million Ukrainian hryvnia, or $433,000, Ukrainian media reported.

Since last year, Ukraine has stepped up its drone attacks on Russian warships in the Black Sea in occupied Crimea.

The Ukrainian intelligence chief, Kyrylo Budanov, said this week that naval attack drones had been able to "paralyze" the Russian Black Sea Fleet.

Russia destroys many of the drones, either using electronic warfare to scramble or shoot them out of the water. But Budanov said the attacks were still a highly effective "deterrent."

Ukraine has also established its first naval drone brigade, the 385th Separate Brigade of Special-Purpose Marine Unmanned Systems.

President Volodymyr Zelenskyy on Thursday presented new colors to the brigade at a Ukrainian Independence Day parade, The Telegraph reported.