Will Russia use nuclear weapons?
STORY: However remote the possibility, these are some of the key issues surrounding the risk of a Russian nuclear strike.
On February 27, three days after announcing the invasion of Ukraine, Vladimir Putin ordered his military command to put Russia's nuclear deterrent forces on high alert.
Two months later, he gave a veiled but unmistakable warning: if the West intervenes in what he calls a "special military operation," he could use nuclear weapons in response.
"If someone intends to intervene in the ongoing events from the outside and create strategic threats for Russia that are unacceptable to us, they should know that our retaliatory strikes will be lightning-fast. We have all the tools for this, things no one else can boast of having now. And we will not boast, we will use them if necessary. And I want everyone to know that."
The U.S. quickly called Putin's comments dangerous, escalatory and totally unacceptable.
“No one should be making idle comments about the use of nuclear weapons or the possibility of using them. It's irresponsible.”
Biden also told Americans not to worry about a nuclear war with Russia.
Biden's comment reflects a widespread view among Western experts and officials that the chances of Russia using nuclear weapons are extremely low.
They say the main aim of Russia's threats seems to be to deter Washington and its NATO allies from direct involvement in the war.
Experts see a range of possibilities, if Russia were to use nuclear weapons;
from a detonation over the Black Sea or an uninhabited part of Ukraine
to a strike against a Ukrainian military target or on a city.
But doing that could endanger Russian troops and draw radioactive blowback on Russia itself.
Some analysts say Washington could opt for a conventional military response rather than a proportional nuclear counterstrike.
NATO might seek to redesign its U.S.-built ballistic missile shield in Poland and Romania to shoot down Russian rockets in future.
It remains unclear whether a Russian strike might make other nuclear states such as India and Pakistan more likely to use such weapons.
