(NewsNation) — NATO warned members of the military alliance about a nuclear-powered submarine that has gone missing from its base in the Arctic Circle, according to media reports.

However, the Kremlin is pushing back on these claims.

An Italian newspaper, La Repubblica, reported on Sunday that NATO sent out a memo on the movements of the Belgorod nuclear submarine, Reuters said.

In the note, NATO said the Belgorod is no longer operating out of its White Sea base, where it had been active since July. Fox News quoted officials saying Russia may plan to test Belgorod’s “Poseidon” weapons system.

Russian officials say the submarine has the ability to create a 1,600-foot nuclear tsunami that could drown coastal cities. The 600-foot submarine, Fox said, was delivered to the Russian Navy as part of Putin’s program to develop and operate a series of new “super weapons.”

However, U.S. officials monitoring the situation say they have not seen Russia prepare any of its forces for a nuclear strike.

When asked about the media reports, Kremlin spokesman Dmitry Peskov said Russia did not want to take part in what he said was the West’s “nuclear rhetoric.”

U.S. officials continue to warn Putin and Russia that there could be catastrophic consequences if it resorts to nuclear warfare.

“I think we should say publicly that if Putin did authorize the use of a nuclear weapon, he would be signing his own suicide note,” former national security adviser John Bolton said on NewsNation’s “Cuomo. “And I think that needs to be clear publicly so that everybody in the Russian military intelligence, domestic security conglomerate knows how much is at risk here.”

Russia is the world’s biggest nuclear superpower. It has 5,977 warheads while the United States has 5,428, according to the Federation of American Scientists.

A DecisionDesk/NewsNation poll shows 39% of Americans think Russia is the country’s biggest threat, followed by China and Iran.

Reuters contributed to this story.