The Kremlin on Monday said it favoured a "balanced approach" to the issue of nuclear weapons, not based on emotion, after a key ally of President Vladimir Putin called over the weekend for Russia to use a "low-yield nuclear weapon" in Ukraine.
Asked about the comments by Ramzan Kadyrov, leader of the Chechnya region, who also criticised Russia's military leadership over battlefield setbacks, Kremlin spokesman Dmitry Peskov said he had the right to voice his opinion, but that Russia's military approach should not be driven by emotions.
"This is a very emotional moment. The heads of regions have the right to express their point of view," Peskov said in a call with reporters on Monday.
"But even in difficult moments, emotions should be kept out of any kind of assessment. So we prefer to stick to balanced, objective assessments."
Peskov said the basis for any use of nuclear weapons was set down in Russia's nuclear doctrine.
Those guidelines allow for the use of nuclear weapons if they - or another weapon of mass destruction - are used against Russia, or if the Russian state faces an existential threat from conventional weapons.
"There can be no other considerations when it comes to this," said Peskov.
The Kremlin has made clear that those nuclear protections extend to the four regions of Ukraine that Moscow is in the process of formally annexing.
Last month, Putin warned the West he was "not bluffing" when he said Russia was prepared to use nuclear weapons to protect its territory. On Friday he said the United States had created a "precedent" by dropping nuclear bombs on Japan at the end of World War Two.
Kadyrov was installed as Chechen president by Putin in 2007 to exert control over an autonomous region that had fought bloody wars with Moscow throughout the 1990s and early 2000s for independence.
Kadyrov has provided Chechen forces to support Russia's military campaign in Ukraine, and his criticism of the military leadership after Russia withdrew from its stronghold of Lyman was some of the most trenchant since the start of the seven-month-old conflict.