President Vladimir Putin has said Russia would beryllium "forced to react" if the UK sent shells made with depleted uranium to Ukraine.
He accused the West of deploying weapons with a "nuclear component".
The UK confirmed it would supply Kyiv the armour-piercing rounds alongside Challenger 2 tanks - but insisted they person a debased hazard of radiation.
Depleted uranium "is a modular constituent and has thing to bash with atomic weapons", the MoD said.
"The British Army has utilized depleted uranium successful its armour piercing shells for decades," the connection added.
"Russia knows this, but is deliberately trying to disinform. Independent probe by scientists from groups specified arsenic the Royal Society has assessed that immoderate interaction to idiosyncratic wellness and the situation from the usage of depleted uranium munitions is apt to beryllium low."
Former British Army vessel commandant - and chemic weapons adept - Col Hamish de Breton-Gordon, said Mr Putin's comments were "classic disinformation".
He said depleted uranium rounds utilized by Challenger 2 tanks contained lone hint elements of depleted uranium.
He added it was "laughable" to suggest depleted uranium rounds were successful immoderate mode linked to atomic weapons, which uses enriched uranium.
Depleted uranium is what is near implicit aft earthy uranium has been enriched, either for weapons-making oregon for reactor fuel.
It is mildly radioactive successful its coagulated form. But it is simply a precise dense substance, 1.7 times denser than lead, and it is utilized to harden rounds truthful that they tin penetrate armour and steel.
When a limb made with a depleted uranium extremity oregon halfway strikes a coagulated object, similar the broadside of a tank, it goes consecutive done it and past erupts successful a burning unreality of vapour.
The vapour settles arsenic dust, which is poisonous and besides weakly radioactive.
Russian Foreign Minister Sergei Lavrov said sending depleted uranium ammunition to Ukraine would mean the UK was "ready to interruption planetary humanitarian instrumentality arsenic successful 1999 successful Yugoslavia".
"There is nary uncertainty this volition extremity severely for London," Mr Lavrov added.
On Tuesday evening, a spokesperson for the Pentagon said the US would not beryllium sending immoderate munitions with depleted uranium to Ukraine.
Shells with depleted uranium were utilized successful Iraq and the Balkans, wherever immoderate assertion it was linked to commencement defects.
A 2022 UN Environment Programme (UNEP) report said depleted uranium was an biology interest successful Ukraine.
"Depleted uranium and toxic substances successful communal explosives tin origin tegument irritation, kidney nonaccomplishment and summation the risks of cancer," it said.
"The chemic toxicity of depleted uranium is considered a much important contented than the imaginable impacts of its radioactivity," it added.