Petty Vladimir Putin could order nuclear strikes at strategic sites in Ukraine in response to a series of crushing defeats on the battlefield, according to a former NATO chief.
The alliance's ex-deputy secretary general hailed Ukraine's territorial gains while warning their counteroffensive in Kharkiv could lead to the despot deploying weapons of mass destruction to save face.
Speaking with the BBC, Rose Gottemoeller said she feared "they [ Russia ] will strike back now in really unpredictable ways that may even involve weapons of mass destruction."
The host quetioned whether she meant a "nuclear strike of some kind", and Gottemoeller said she did.
"We've been concerned from the outset of this crisis with Putin rattling the nuclear saber that he might put in play for a nuclear demonstration strike," she added.
While avoiding the use of Moscow's flagship Intercontinental Ballistic Missiles, like the world-ending Sarmat "Satan II", she said the Kremlin would likely order a "single strike over the Black Sea" or a "strike at a Ukrainian military facility".
Such a strike would terrorise the Ukrainian population and make Kyiv's allies more wary of involving themselves in the conflict.
"The goal would be to try to get the Ukrainians in their terror to capitulate," Gottemoeller said.
"I do worry about that kind of scenario at the moment. I think the Ukrainians seem well prepared to stay the course but we will all have to be ready to stay the course, come what may."
Ukraine worked on Wednesday to secure territory reclaimed from occupying Russian forces in a swift counter-offensive and reiterated plans to win back all occupied regions.
In a Tuesday evening address, President Volodymyr Zelenskiy said around 8,000 square km (3,100 square miles) have been
liberated by Ukrainian forces so far this month, apparently all in the northeastern region of Kharkiv.
"Stabilisation measures" had been completed in about half of that territory, Zelenskiy said, "and across a liberated area of about the same size, stabilisation measures are still ongoing".
Reuters was not able to immediately verify the full scope of battlefield successes claimed by Ukraine. The total area cited by Zelenskiy is roughly the size of the Greek island of Crete.
Asked whether Ukraine has reached a turning point in the six-month war, US President Joe Biden said it was hard to tell.
"It's clear the Ukrainians have made significant progress. But I think it's going to be a long haul."
The White House, which has provided billions of dollars of weapons and support to Ukraine, has said the United States is likely to announce a new military aid package in "coming days".
