Russia suddenly brandishing old underwater rifle

TASS, the Russian news agency, always publishes things for a reason. So when it releases a video extolling the virtues of underwater weapons used by Russia frogmen (those trained in tactical scuba), it should raise eyebrows.
The APS Automatic is a weapon specifically designed to shoot 5.66-mm ammunition underwater at a rate of 500 rounds per minute. These gas-powered assault rifles have better range and penetration than a speargun. Like a speargun, they don’t work so well on land. The barrel it isn’t rifled and has a shield that breaks up bubbles to help frogmen shoot from concealment.
These weapons have been around since the mid-1970s.

Frogmen really do only a few things—surveillance, sabotage, and fighting other frogmen. So the Russians are signaling that their anti-terrorism forces are ready for underwater attacks from what the article called “probable enemies” and “subversive forces…operating in areas of basing of the Baltic.”
As they were during the Cold War, the Baltics these days are a flashpoint of tension between Russia and NATO. The country has two naval bases here: Baltiysk in the isolated patch of Russian turf known as Kaliningrad (the part of Russia stuck between Poland and Lithuania that isn’t connected to the rest of the country) and another base in Leningrad Oblast. These host small but strategic fleets that bring the Russian sphere of influence to eastern Europe. It’s important because Russia feels insecure on this border, watching NATO expand and seeing some of its “buffer zone” of client states lean toward the West. Each of these bases has anti-aircraft weapons that blanket the Baltic Sea and extend into states with deteriorating relationships with Russia, like Poland.
In July, the government purged the leadership of its Baltic sea fleet, a sure sign that Vladimir Putin wants the bases run well in preparation for future geopolitical or even military confrontation. “Leningrad naval bases are designed to ensure the protection of ships and submarines of the Baltic fleet from sabotage and reconnaissance units,” the TASS article says.
The very idea that these underwater weapons are needed presumes that someone with an agenda will be sabotaging them. A few frogmen in underwater vehicles, armed with shaped charges, could do a lot of damage. A successful mission could be accomplished without blame or attribution, which is the kind of “low-intensity, hybrid” warfare that Putin has used successfully in Crimea, Georgia, and Ukraine.
The U.S. Navy SEALs or German counterparts come to mind. NATO also has a Special Operations command and fields these troops as part of their Very High Readiness Joint Task Force. NATO leaders formed the VJTF in 2014 as a land brigade with some special forces thrown in. Interestingly, non- NATO Baltic countries like Finland and Sweden joined the Response Force nearly 10 years ago, and the Ukraine and Georgia began its contributions around 2015.
The United States has also looked into underwater weapons, and has developed systems using sea lions and underwater grenades. The research received a renewed focus after the US found al-Qaeda plans to launch underwater attacks on ships, say US media reports.