In a recent communication with Russia, Western countries have moved on from abstract warnings to outlining concrete measures they would take in response to Russia’s use of nuclear weapons in Ukraine. This is an important shift in the West’s approach to nuclear deterrence.

Kuleba said that before Russia’s full-scale invasion, Ukraine had already told its Western partners that the warnings they were directing at Russia were too abstract: "The Russians took this as an invitation because President Putin only understands the language of power," Dmytro Kuleba, Ukraine’s Foreign Minister, said this in an interview with TSN, a Ukrainian daily news program

"When Russia rolled out its misinformation campaign about the ‘dirty bomb’, President Zelenskyy and I had countless conversations with Ukraine’s international partners. It’s crucial that our partners told us that they have told the Russian Federation what exactly will happen if it deploys nuclear weapons. We spoke the language that President Putin understands," Kuleba said.

He explained that this meant "a change in approach: from abstract warnings (we will do something if you do it) to outlining concrete measures which Russia cannot prepare for or mitigate."

"This suggests that the West is taking this threat very seriously. At the same time, Russia continues to escalate, having recently conducted the Grom nuclear drills. However, the circumstances are totally different now. We have no grounds to assume that Russia is preparing to carry out a nuclear strike on Ukraine right now. Though of course, they are trying to escalate, to suggest a particular way that the events might unfold," Kuleba concluded.

Fear that Russia might deploy nuclear weapons in Ukraine has escalated following Russia’s public claims that Kyiv was preparing a false flag operation involving a "dirty bomb". Both Ukraine and the West have denied these claims.

The United States has no indications that Russia has decided to employ a nuclear weapon, biological weapon or chemical weapon, a US military official told reporters on 24 October.

US President Joe Biden has said that Russia will face a decisive response if it deploys nuclear or chemical weapons in Ukraine; he has not however specified what that response might look like.