Russian President Vladimir Putin is unlikely to act on his threats to use nuclear weapons in the war over Ukraine, according to the Stockholm International Peace Research Institute (SIPRI).

“I don’t think that nuclear war is a likely result of this crisis,” SIPRI director Dan Smith said.

“But unfortunately, when nuclear weapons exist, then there is of course always that small possibility. And it would be catastrophic.’’

Putin announced that he was sending Russian troops into Ukraine early on Thursday, launching a long-feared invasion of Russia’s neighbour.

In his speech, he pointed out that Russia was now one of “the most powerful nuclear powers in the world.’’

According to SIPRI’s last annual report, released in June 2021, Russia had more than 6,255 of the 13,080 nuclear weapons owned by the world’s nine nuclear powers early last year.

The United States, for its part, had 5,550 warheads.

Smith refuted the argument that nuclear arsenals contribute to international stability.

“People who make that argument should look at the instability which we are experiencing at the moment and understand: No, nuclear weapons do not contribute to stability.

“They contribute to mutual suspicion, hostility and instability,’’ he told dpa.

Many top politicians have described Russia’s invasion of Ukraine as a dark moment in European history.

Historically, there has not been a more dangerous situation since the Korean War of the early 1950s, Smith said.

There was also a confrontation of military forces in the Cuban Missile Crisis – but now the war is actually being waged.

Unlike at those moments in history, “it’s not easy to see what the diplomatic resolution of this crisis will be,’’ he said.

On Putin’s motivations for his moves on Ukraine, Smith said that Russia’s security concept was based on having some power and influence in areas outside its own borders.

For Putin, these surrounding states should ideally be “compliant’’ like Belarus or “disabled like Georgia, according to the expert.

The government in Kiev, he said, was not compliant.

Nevertheless, Putin wanted to ensure that Ukraine can act as a reliable security buffer towards the West.

But thinking of Ukraine as a buffer state is flawed, in Smith’s view.

Instead, Ukraine could be approached as a nation that might enjoy potentially good relations with both Russia and the West.

“That would be the aim,’’ he added.

“Then everybody’s security will be met’’, Smith said, before pointing to the civilians of Ukraine.

“They’re not there to be pawned in somebody else’s power game.’’