Russian President Vladimir Putin has accused "the collective West" of using “weapons with nuclear components,” after the UK said it would send Ukraine depleted uranium (DU) ammunition on March 22.

Putin made the statement during a joint press conference with Chinese leader Xi Jinping, who is in Moscow on a three-day state visit. Putin criticised the British government's announcement of its planned weapons deliveries to Ukraine. 

British Minister of State for Defence Annabel Goldie said the same day that the UK would be providing Ukraine with "ammunition, including armour-piercing rounds which contain depleted uranium."

“Such rounds are highly effective in defeating modern tanks and armoured vehicles,” said Goldie, in response to a question from a crossbench MP, Meduza reported.

Putin framed the planned deliveries as another instance of Western countries twisting Russia's arm and said Russia would be “forced to react” to the development. 

“If all of this does take place, Russia will be forced to react, in view of the fact that the collective West is already starting to use weapons with nuclear components,” said the Russian president as cited by Meduza.

Depleted uranium is the stable uranium isotope that is left over after enriching uranium to separate the unstable 235 isotope that is used in nuclear reactors. While it is radioactive, it has a long half-life and emits low levels of radiation and is not considered hazardous to health. DU is extremely dense, making it very hard and so ideal for use in armour-piercing shells. DU weapons have nothing to do with nuclear weapons, as there is no chance of a chain reaction.

Reacting to the news, Russian Defence Minister Sergey Shoigu warned that "another step up the ladder has been taken, with fewer and fewer steps remaining," while Foreign Minister Sergey Lavrov said Western countries "have already lost their bearings in terms of their actions and how these actions undermine strategic stability around the world."

Lavrov went on to say the West “violates international humanitarian norms, as it happened in 1999 in Yugoslavia,” referring to the Nato-led military campaign in Serbia, where Nato forces also used DU shells.

Since Russia launched a full-scale invasion of Ukraine in 2022, Putin and his government have often threatened the West with Russia's nuclear arsenal. On February 21, Putin announced Russia's suspension of compliance with the New START Treaty, the only nuclear arms control treaty then in effect between the US and Russia.

According to the International Atomic Energy Agency (IAEA), depleted uranium is 60% less radioactive than uranium found in nature, making it suitable for use as ballast in ships and aircraft. It's also been used in the manufacture of armour-piercing ammunition and in strengthening the armour on tanks and armoured vehicles.