Vladimir Putin today promised to "respond" to Britain's plans of sending ammunition to Ukraine.
Russia's Defence Minister Sergei Shoigu also warned there are "fewer and fewer steps" to a nuclear collision.
Putin said some of the ammunition that Britain is sending to Ukraine includes armour-piercing rounds which contain depleted uranium.
He said that supplying Kyiv with weapons that contain nuclear components will result in Moscow responding if the delivery goes ahead.
He said: "The United Kingdom ... announced not only the supply of tanks to Ukraine, but also shells with depleted uranium. If this happens, Russia will be forced to respond accordingly, given that the West collectively is already beginning to use weapons with a nuclear component."
Putin made the comments after meeting with Chinese leader Xi Jinping where they signed an agreement to bring their relationship into a "new era".
Shoigu also echoed Putin's warning and said the world is just mere "steps" away from nuclear disaster.
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Shoigu said: "Another step has been taken, and there are fewer and fewer left."
When asked whether this meant that the world was closer to a nuclear collision, he replied: "It was not by chance that I told you about steps.
"There are fewer and fewer."
Depleted uranium is used in weapons because it can get penetrate tanks and armour.
If dust gets into people's lunch and vital organs it can be a health risk.
When asked about the ammunition, Shoigu said: "Naturally, Russia has something to answer this with."
Earlier today, two of Putin’s key war chiefs were bitterly fighting each other today as the dictator begs Chinese leader Xi Jinping for urgent military aid.
Head of private army Wagner, Yevgeny Prigozhin, bluntly and publicly warned defence minister Sergei Shoigu that he will lose all military gains in Bakhmut if he fails to act fast.
Shoigu evidently shunned Prigozhin who soon after launched a scathing attack on the defence minister’s "scumbag" fitness blogging son-in-law.
He did the same when the Wagner boss recently accused Shoigu of refusing to provide ammunition and shells for the private army’s advances.
His answer was to cut Prigozhin’s telephone lines to the military high command.
