According to TASS on Monday, which cited an unnamed defense source, Russia has built the first batch of Poseidon nuclear-capable super torpedoes that are being created for use on the Belgorod nuclear submarine.

President Vladimir Putin has made repeated indications that Russia will not yield since a somber address on New Year’s Eve that painted the West as Russia’s real foe in the conflict in Ukraine. He picked his top general to lead the war and sent hypersonic missiles to the Atlantic.

U.S. and Russian officials have both described Poseidon as a new category of retaliatory weapon, capable of triggering radioactive ocean swells to render coastal cities uninhabitable.

“The first set of Poseidons have been manufactured, and the Belgorod submarine will receive them in the near future,” TASS, a state news agency, quoted the source as saying.

TASS said the main components of Poseidon, including a nuclear reactor to give the torpedo its own power source, had been successfully completed. The crew of the Belgorod nuclear submarine has also completed tests with models of the torpedo, TASS said.

The defence ministry did not immediately respond to a request for comment.

Putin first announced what would become known as Poseidon in 2018, saying it was a fundamentally new type of strategic nuclear weapon, confirming it would have its own nuclear power supply.

There are few confirmed details about the Poseidon in the public domain but it is essentially a cross between a torpedo and a drone which can be launched from a nuclear submarine.

Russia’s defence ministry has shown videos of the 24-metre Poseidon, known as Kanyon by NATO, including simulations showing it destroying an enemy aircraft carrier and hitting the shoreline.