Tactical nuclear weapons against Ukraine by the Russians.
The hypothesis is not so strange according to the New York Times.
According to the authoritative US newspaper, senior military officials of the Kremlin have recently gathered in multiple meetings to discuss when and how Moscow could use a nuclear weapon, thus helping to increase the concern of Washington and allied capitals.
Some senior American officials, acting as sources close to the paper, said Putin did not attend the meetings
but also said they saw no evidence that the Russians are moving their weapons to the border or preparing to attack. .
William J. Burns, director of the CIA, however, previously said that Putin's "potential desperation" to win Ukraine and setbacks in the war "could lead Russia to use a nuclear weapon."
The information reported by the NYT was released internally in mid-October, when Moscow was spreading the unsubstantiated news that Ukraine was planning to use a so-called "dirty bomb", a conventional explosive containing radioactive material.
The Pentagon estimates that Russia has a supply of 2,000 tactical nuclear weapons, designed specifically for use on battlefields: never used before in combat, they can also come in the form of missiles or artillery shells.
Only President Putin has exclusive authority over the use of a tactical device
and could make the decision to deploy it regardless of the views of his generals.