Footage and images shared online appear to show the Ukrainian navy using underwater drones in their fight against Russia.
Its navy has already displayed a mastery of surface sea drones as an effective strike weapon but does its latest underwater unmanned technology show how the country has now gone a step further to herald a new era of underwater drone attacks?
The footage released online, while not yet verified, is said to show Ukraine's underwater drone, the Marichka, undergoing testing.
Other designs, as seen in a schematic shared widely on social media, have all pointed to Ukraine moving in this direction but it is not alone.
Samuel Bendett, a Russia advisor at the Centre for Naval Analyses said: "Multiple countries are actually developing these type of submersed, unmanned underwater vehicles or UUVs, Russia included.
"As well as the United States, China, and a number of other countries.
"They're being developed for conducting surveillance and reconnaissance below the waters, and some of them can actually be armed to attack surface and sub-surface vessels.
"We also have non-state actors like certain drug cartels in Latin America that actually built semi-submersible vessels that can cross the Atlantic.
"So the knowledge for building both military and commercial type vessels, both fully and semi-submersible has been around for many years at this point.
"We're probably not far away from some kind of a UUV trying to attack or damaging Russian naval assets."
During the ongoing conflict against Russia, the Ukrainian Navy has repeatedly demonstrated the effectiveness of using drones at sea.
Defence analysists are now speculating that a new era of underwater unmanned military technology might be entering the conflict as the Ukraine war rewrites the military playbook.
The low profile of surface sea drones gives a degree of stealth, but a submersible or semi-submersible design makes them harder to detect and intercept, whether they’re engaged in attacking of simply clandestine surveillance of ports or vessels.
Russian defence manufacturers are also working to keep up with the development of such technology.
Some experts believe Ukraine's mastery of sea drone tactics is playing to a new arms race in naval drone design, above and below the surface.