Although the West is becoming more united in its approach towards beleaguered Ukraine, there are fears this could push a cornered Vladimir Putin to trigger nuclear war.
But just how realistic are these concerns? Here’s everything you need to know.
What nuclear weapons does Russia have?
Russia has the largest stockpile of nuclear weapons in the world, although it has cut down on its supplies since the Cold War.
The Nuclear Threat Initiative claims that, as of 2022, the country has approximately 6,257 warheads.
It also has both smaller tactical weapons along with larger strategic missiles.
Tactical nuclear weapons vary in size and strength, but – in the very unlikely event Russia does start to use its nuclear supply – Moscow will probably deploy these first.
They can be one kiloton (the equivalent to 1,000 tonnes of explosive substance) while the larger ones can go up to 100 kilotons.
Russia’s largest strategic weapons are believed to be at least 800 kilotons.
For context, the atomic bomb that killed around 146,000 people in Japan during Second World War was 15 kilotons.
But, it’s important to note that the impact from each of these weapons would depend on the size of the nuke, how far above the ground it detonates and the surrounding area.
Aside from Russia, the US, the UK, China, France, Pakistan, India, Israel and North Korea are all known to have nuclear weapons.
Russia – along with the US, UK, China and France – also signed the 1968 Treaty of Non-Proliferation promising to stop the spread of nuclear weapons.
What has Putin said about the weapons?
Putin has been holding his nuclear arsenal over the West ever since he launched his attack on Ukraine, and has claimed that Russia is “one of the most potent nuclear powers and also has a certain edge in a range of state-of-the-art weapons”.
The country’s foreign minister Sergei Lavrov then warned in April that the risk of nuclear war was “considerable” because the West continues to supply Ukraine with weapons, even though the West has done this since the invasion began.
Russia has also repeatedly promised that its nuclear weapons will be used “exclusively as a means of deterrence”, although it’s not entirely unclear what would qualify as a provocation to Moscow.
Why would Putin deploy them now?
The invasion has not gone to plan
Russia’s invasion of Ukraine has definitely not gone as smoothly as the Kremlin originally planned.
The Russian forces’ attack has been barbaric and caused millions of Ukrainians to flee. But, with skyrocketing losses and no real victory in any part of Ukraine, the strength of the nation’s resistance continues to take Russia by surprise.
The West is teaming up
Putin’s invasion was at least partially motivated by his fears that the West, particularly Nato, was uniting against him.
Since his invasion, Ukraine has decided to step back from the defence organisation. However, Finland – which also shares a border with Russia – has announced it plans to join Nato as soon as possible.
Sweden is considering it as well, despite being neutral historically.
The West appears to be doing the exact opposite of what Putin supposedly wanted and is coming together.
The UK also went further than any Western country and pledged to send troops to Sweden if it comes under attack from Russia on Wednesday.
The deputy chairman of the security council, Dmitry Medvedev, said on Thursday that as Nato is still sending weapons to Ukraine, it “increases the likelihood of a direct and open conflict between Nato and Russia”.
Such a conflict, he claimed, could turn into a “full-blown nuclear war”.
Russia’s isolation
The sanctions in the West are starting to have a real impact on Russia, as prices rise and goods are harder to buy.
On top of that, the West is gradually severing its ties with the country’s oil and gas industries.
Even Germany revealed on Thursday that it believes it can cope with a boycott of Russian gas by this winter, despite being previously reliant on the export.
But do people think Putin will actually use them?
Director of national intelligence in the US, Avril Haines, warned on Tuesday that defeat in Ukraine could lead to an escalation of tensions.
While she clarified that the Russian president is not expected to use a nuclear weapon unless he saw an existential threat to Russia or regime, there is a chance that losing in Ukraine could fall into such a category.
Haines said: “The current trend increases the likelihood that President Putin will turn to more drastic means, including imposing martial law, reorienting industrial production, or potentially escalatory military actions to free up the resources needed to achieve his objectives as the conflict drags on, or if he perceives Russia is losing in Ukraine.”
However she added that she expects there to be some form of “signalling beyond what he’s done thus far before” if he were seriously considering it.
Former US under-secretary of defence for policy, Walter Slocombe, also told the US think tank Atlantic Council: “There is some non-zero (perhaps a worryingly high 1 or 2%) risk he will carry out his threats.”
Not everyone is as concerned though. When Russia moved to put its nuclear deterrent on high alert, defence secretary Ben Wallace dismissed it.
He said the move was an attempt to distract “the world and the public from what he’s actually doing in Ukraine”.
Ukraine’s foreign minister Dmytro Kuleba said at the end of April: “This only means Moscow sense losing hope to scare the world off supporting Ukraine.”
According to nuclear expert James Acton, from the Carnegie Endowment for International Peace in the US, Putin would use the weapons only to “terrify everyone and get his way”.
Ukraine is also very close to Russia, geographically, and Putin claims the two are one country, meaning the use of a nuke is a high risk move for the Kremlin.
Although the Russian leader has crossed lines before (see: invading Ukraine) others such as Kings College London’s nuclear expert Dr Heather Williams think that Kremlin’s dependence on China would deter such a drastic move.
Speaking to the BBC, she said: “China has a ‘no first use’ nuclear doctrine. So if Putin did use them, it would be incredibly difficult for China to stand by him. If he used them, he would probably lose China.”
What would happen if Russia did use nuclear weapons?
In the unlikely event Putin were to use his nuclear power, experts believe he would deploy the weapons in Ukraine and they would be used against the military rather than civilian targets.
Former senior staff member for the National Security Council in the US, Jan Lodal, told the Atlantic Council: “The sequence would look like this: Putin would first create a ‘provocation’, then hit a high-value target such as Kyiv in hopes of getting Ukraine to accept ‘peace at any cost’.
“However, he would also seek to avoid any potential spillover, such as radiation, into any NATO state.”
However, it’s not clear how the West would respond to a nuclear attack.
The UK and its allies would probably want to avoid escalating the situation, but how authority in the face of Putin’s dangerous actions at the same time.
So far, US intelligence suggests there has been no significant change in Russia’s storage of weapons, so they are not deployed and ready to fire.
As nuclear expert James Acton told the BBC: “Once you have crossed the nuclear threshold, there is no obvious stopping point.
“I don’t think anyone can have any confidence of what that world would look like.”